I currently have a hybrid, and I really enjoy riding. I just got it in July. I'm thinking about getting a roadbike sometime next season. But, I'm not certain. I've already spent my tax return in my head a million times. Anyway, I thought that over the winter months I could spend some quality time shopping for a bike without pressure to buy it now.

I'd be skeptical trying it out in the parking lot when it's winter... but can you get an idea for the basic fit of a bike inside on a trainer? Narrow the selection down to 3-5 or so or 2-3 and then come back later and take them for a spin?

Also, for a total rookie question, how do you shift on a roadbike? I've noticed the little switches near the brake levers on some bikes... how does that work? I'll feel like a total putz trying to shop for a roadbike having never been on one in the first place, but I don't know anyone in my local club well enough to ask to try theirs.