I agree that 15 minutes seemd pretty cursory, but I had been making gradual adjustments toward "ideal" position over the past month and had been "fit" by the non-roadies where I bought the bike.

The longer ride went well. I had some lower back pain the last few miles, but I know at least part of that is inflexibility. The arm pain and saddle pain are gone, and I was able to stay on the bike for 3.5 hours of saddle time without pain. I'm working on stretching my tight hamstrings and lower back, and if I continue to have problems, I'll either go back to this shop or try to figure out who the best guy in town is and go to him. We also have a sports-oriented physical therapy place in town that does fittings, so I may decide to go there.