Would you take someone learning to ski to the top of a black diamond slope, slap them on the back and wish them good luck? Sounds like a recipe for a faceplant in a snow drift, if lucky... Or something much worse, if not so lucky.
7D is a great camera. I've been using a pair of them for a couple years now. But it certainly is not a camera I'd recommend to a beginner. It's fairly advanced and complex, requires some level of experience to get the best out of it... all the way from the time of image capture through post processing the images back home on one's computer.
Too often we see postings here from people frustrated trying to learn to use 7D. Even with 25-30 years experience with DSLRs, I found the 7D fairly frustrating to learn to use and almost gave up on it during the first two or three months. That was mostly due to all the additional complexity of the AF system and the lack of good info on it two years ago when it was brand new and I go my cameras.... There's a lot more guidance out there now, thgankfully. But it still takes some effort to find it and learn it.
7D has little automation to support newcomers while they learn to use an SLR. It's designers assumed a fairly advanced user... semi-pro or full professional. It is easily the most pro-oriented APS-C camera Canon has produced to date (and was long overdue, too).
I also would not necessarily recommend 7D to someone planning to mostly shoot landscapes and portraits. It's forte is shooting sports/action... And, while you certainly can shoot landscapes and portraits with it, you are essentially paying a 40-50% premium for features you're unlikely to need or use. 60D can shoot landscapes and portraits every bit as well, and is merely an "advanced amateur" model by design, offering somewhat more automation that a newcomer can use while they learn. The T3i and T2i are even less expensive and even more beginner-oriented. All four models have virtually identical imaging potential.... they share almost the same 18MP sensor and Digic 4 processor.
Besides... The chunk of money saved buying a "lesser" model can be put toward buying better lenses, which will ultimately make much more difference in your images than the choice of camera models will.
One small exception... 7D does have a unique macro mode when shot with AI Servo AF, but only when using one of several Canon macro lenses (AFAIK: EF-S 60mm, EF 100mm L or USM, and 180mm). A lot of macro shooters use manual focus techniques anyway, for them this might not be a very big "selling point" for the 7D.
At the moment, the most "ideal" Canon for landscapes, portraits, possibly even macro is the 5DII. Of course, that's an even more expensive camera than the 7D and requires more expensive, larger/heavier lenses to get the best out of it. But, 5DII gives max possible detail with it's FF sensor and offers the most control over depth of field, for portraits and macro. And, actually, 5DII is a pretty simple camera to use. Besides it's video capabilities, it only has a few different or additional features, compared to 50D or 40D. 60D is actually probably more complex in some respects. But they all, incl. 5DII, are more straight-forward cameras than the 7D.
Any crop sensor model such as 60D, T3i/600D or T2i/550D is a little bit of a compromise... But have tons of potential for great images, just in an easier to use package while learning the ropes.
IMO, the OP has a choice.... Either sell the 7D and replace it with one of the models designed to be more friendly to newcomers, or learn to use the 7D.
Forget about using M much, until you know what you are doing. There is nothing wrong with using the auto modes (pros use Av, Tv and even P extensively, I can assure you). And there are are plenty of tricks to learn even with some automation helping you. Sure, experiment and learn what M can do for you (there are times it's the best choice... but there are other times when Av or Tv or P is the best choice, too).
Yes, get and read and reread "Understanding Exposure" as a starting point. That book can serve as a good guide for getting started with almost any camera.... And even the most experienced users reading it will usually find some helpful info and suggestions.
And, as already suggested, get and read one or more of the 7D specific guide books, too, if you stick with that camera. If you change cameras, get the guide book specific to it. These pick up where the manual leaves off, and often have more "real world" and hands on examples about using the gear.
There are also online tutorials and videos... B&H Photo has a bunch of 7D specific videos.
As to lenses...
Well I really don't like to over complicate things too much initially. So add lenses a step at a time.... not all at once.
Your 28-135 is a really nice "walk around" lens... affordable, fast and close focusing, with reasonably good IS and decent build quality... capable of very good IQ (rivalling some L-series lenses). It covers a nice, convenient range of focal lengths...
It's just not very wide, though, on any crop sensor camera.
For landscapes in particular, you might want to consider something wider such as Canon 10-22, Tokina 12-24, Sigma 10-20 or Tamron 10-24. Personally I think the Canon the best of the bunch, but it's also the most expensive by a big margin. I use the Tokina 12-24, which sells new for about 35% less than the Canon, and am quite comfortable recommending it. I haven't tried the current version of the Sigma or the Tamron.
You say your are interesed in portraits... IMO the 50/1.4 and 85/1.8 are about the best value vs performance and most portrait-appropriate focal lengths for use on 7D or any other crop camera. For someone who wants just occasional use, the 50/1.8 is a bargain... but it's not very durably built, has slower and less dependable AF. The f1.4 lens improves on all of those and offers some modest image quality enhancements as well. These prime lenses (as opposed to zooms) all have large enough apertures to stongly blur down backgrounds, often important shooting portraits. A bit more expensive alternatives are the Sigma 50/1.4 and 85/1.4. Premium lenses for the purpose, and probably the most specialized for portraiture, are the Canon 50/1.2L and 85/1.2L II.
I don't want to give the impression that only 50mm and 85mm focal lengths are the only ones usable for portraits. They just happen to give the most traditional angles of view for that type of photography, on crop cameras. For some kinds of portraits, in addition to the 50mm and 85mm sometimes I also use 20/2.8, 28/1.8, 135/2... and even some others. Some folks might choose a single lens that's in between, such as a 60mm (Canon or Tamron) or 70mm (Sigma), all of which are actually macro lenses and might serve double duty, or a slightly longer lens such as Canon 100/2 or 100/2.8 Macro.
Speaking of macro... just about any lens can be used as a macro or near macro, simply by adding some macro extension tubes behind it. I consider the Kenko DG tube set (of three) to be good value.
A true macro lens is more convenient, though, and can potentially give the best possible image quality. There are a number of excellent macro lenses.... I usually recommend one in the 60mm to 105mm focal length range to start with, simply because they are a good compromise of working distance and ease of use for handheld shots.
Still, it never hurts to have a set of macro extension rings... they can be used with true macro lenses, too, as well as serve some other purposes (such as improving the close focusing distance of a telephoto lens).
Macro is another huge topic... Too much to try to cover well here. Get and read books such as John Shaw's "Close-ups in Nature" and/or others from Tim Fitzharris, Joe MacDonald, Heather Angel, Nial Benvie and some other folks.
Your interests don't really call for one, but for general purpose telephoto a lot of folks enjoy one or the other of the Canon 70-200. These are true workhorse lenses, durable and with high image quality. A zoom is more versatile than a prime. The f4 versions of 70-200 are more portable and handholdable. The f2.8 are a lot bigger/heavier, but still handholdable. If you have a few fast prime lenses like those mentioned above for portraiture, you might be fine with the f4. I do recommend getting the IS version of any 70-200, if at all possible. Stabilization is very helpful on telephotos, in particular.
If you were interested in sports and/or wildlife and birds, you might want an even longer telephoto instead... A zoom such as Canon 100-400 IS or Sigma 120-400 OS or 150-500 OS are good, versatile starting points. None of these has particularly large apertures, which makes them more affordable and practical for handheld shots... But also means you'll need reasonably good light and will have somewhat limited ability to blur down backgrounds.
Beyond these lenses... consider eventually adding a flash and decent tripod. Flash can be very helpful for portraits, of course... But also can be important for macro (doesn't have to be a macro flash, specifically... a single, standard flash works pretty well for macro too, with some simple tricks). Don't cheap out on the tripod... It can be a once in a lifetime purchase and you are more inclined to use a nice one... A tripod is as much a learning tool that forces photographers to slow down a bit and thing about their shooting, as it is a means to get nice, sharp shots.
Learn to walk before you try to run! I shudder a little when I see the words "7D" and "beginner" in a post heading! You can learn shooting DLSRs with 7D, it just will take some additional effort and study... staying away from the more advanced stuff and keeping it as simple as possible while you are learning.
