Hi softie, I'm not as experienced as most of the people on this forum, but I'll toss in my two cents. I think something like a Trek 7.5 sounds great for your situation. I actually have a 7.5 WSD that I've just started using as an errand bike. It was my primary bike until just a couple of weeks ago, and has served me well. I'm short and have a small bone structure so a WSD is perfect for me; my daugter is 5'6" with a medium body frame and the regular bike frames work well for her. Even though I am currently doing most of my bicycling on a road bike, I still love the Trek 7.5. It is simply a great bicycle. My daughter has a Trek 7.2 at college and it is perfect for her needs.

Good luck!