Right now I'm riding my friend's bike (slightly too big), and I can only do 5 miles on it . Sad, but I'm having a great time, and hoping to get stronger, so hopefully I'm not being too optimistic with my goals.

Still, it would be great to have a reliable bike that I won't "outgrow" too soon, so I'll look into the suggested options, and test drive the Trek FX again (and I'll ask the salesperson to make adjustments to see if it helps).

Thanks again for all the help! I really do appreciate it.