Wow. That's a tough one. The geometry on every bike is different. Being able to test ride is really important. You say that your town only has a few bike shops, but what about neighboring towns? How far would you have to drive to the next big town with more selection? It might be worth it.

I'm small, too (just under 5'). My bike shop caters mostly to mountain bikers (about 70% off road / 30% road). So they had lots of mountain bikes in stock for me to test. But when I bought my road bike, they didn't have anything close. Their Trek sales rep was able to find a 47cm frame for me to try. It didn't have the same components as my bike, but I could at least test fit the frame.

I'd suggest you do the research online (or in catalogs, etc). But then try to find a shop that has bikes you can test ride. You may have to make some phone calls and drive a little, but it doesn't look like you have much of a choice.

Good luck!