This is probably stupid, but I'm clueless. Background: I bought a bike from my LBS 8 years ago, and all I knew at the time was that I really enjoyed biking on a service mission for my church using "stock" bikes (no clue anything about them either). The salesman suggested I get a hybrid, comfort bike, since I had no idea what type of biking I'd really be getting in to. I don't even know what size it is! That bike has done great for me, but I'm thinking I want to get a "real" road bike now. I enjoy distance rides, and I'd like to participate (probably not "race") in biking events. (An insane goal I have is to complete LOTOJA, 200+ miles through 3 canyons from Logan, UT to Jackson Hole, WY.)
So how do I figure out what size frame I need to be looking for? We're pretty tight with money, so the only way I'll be able to afford a road bike is Craigslist or something like that. (It'll be enough of a struggle to convince my husband to stay with the almost-3yo and baby twins while I go out; asking to spend lots of money on top of that will not go over well.) I'm 5' 5", medium build, and have quite a bit of weight to lose (not the babies' faults). Any advice would be appreciated!