Attempting engagement photos (for fun) - suggestions?

I am just a novice photographer who is looking for a new subject to photograph (I have enough photos of my dog and my husband to fill a thousand albumsops. My good friend is engaged and I am meeting up with her and her fiance tomorrow for dinner. They agreed to meet me a little early so I can use them to practice. Thought it would be fun to try and do engagement photos. Keep in mind that they have hired a photographer and are not counting on these shots in any way. This is much more for my benefit than theirs. But I am sure they would be happy if they get some good shots out of the deal.

Questions:

1. There is a nice riverwalk area that is by the restaurant that I want to use. It will be about an hour before sunset so I should still have enough light. My equipment is listed in my sig. . .should I just stick with my nifty? Or could I make the 70-200 work? I plan on bringing everything so I can certainly swap out - just curious where I should start.

2. Any tips/tricks from the seasoned pros? Any good threads that you can recommend? I have been looking at other poster's engagement photos and have some ideas, but am always looking for more.

That's about it. Thanks in advance!

I would create a contact sheet of about five or six engagement poses you find on the web and like. Print it out (B&W OK), stick it in your pocket, and take it to the shoot. Show them the poses so that they can see what you're trying to do. Run through the poses using your crib sheet. You said you are going to shoot at sundown. I like to shoot them with the setting sun behind them Wait until just after the sun sets for two reasons - backlight is much less than with the sun still on the horizon, and the sky color is better. Use the camera on manual, and set the exposure on the sky without the sun in the frame. Use the sky adjacent to the sun. Let your automatic flash determine the exposure on the couple themselves. Don't forget to get them kissing. If you are going to do this before the sun sets, be sure you have enough light. I use up to 5 strobes for beach weddings.