wildlife backcountry: wide and tele

So through my research it appears to me that a wide angel and tele would be best for most situtations. so that being sad and tied into being in the backcountry where everything you carry adds up especially if your gone days at a time it would seem this should work.

17-40 f4 and a 100-400L

i know the middle range is missing but trying to go light as possible and get most out of it. what do you think?

What subjects? Would make a big difference in which lenses are best.

That is a lot of range, focal length wise. If you bring a tripod that should do you.
You could bring a 12 or 25mm extention ring and make your lenses focus super close for macro like shots.

I'm guessing that a number of nature photographers will need a setup along those lines to cover everything from landscapes through to wildlife. On your 20D the 100-400mm would be just stunning.

There is a gap in between the two lenses, but depending on your shooting habits it may not be critical. In the past I made do with the kit lens and the 100-400mm...no issues.

If you want something in between, and are also keen enough on macro work to need a true macro lens, then you may want to consider the EF-S 60mm macro. It's supposed to be a good lens, and although it's EF-S, you should have no issues unless you are going to upgrade your camera body quickly.

That combo should cover everything you'd need.