Hi Janet, I rode a heavy bike last year like you, and this year upgraded to a Trek FX (I think probalby similar to the Quick). Flat handlebars, skinnier tires, lighter, but not quite a road bike. Riding is so much easier this year. However....I do wish that I had tested some road bikes. I ride with some beginner groups and can keep up, but I'm not sure I could keep up with the next level of riders. I can't speak to the back pain you might feel on a road bike, but I'm sure the other ladies on here will have good advice for you. Just wanted to suggest that you consider a road bike, because you sound like you are in better shape than me Have fun test riding.