Woot! Sounds like great fun. Congratulations 
It's hard to tell from your aches and pains. Could be fit, could be conditioning. It sure wouldn't hurt to have someone go through your fit before you start ramping up the mileage much more.
Hot spots could be a lot of things too, but one easy culprit is just shoes being too tight. Your feet will swell over a long ride - you might just try loosening the straps a bit about halfway through. Still, a lot of people do better with pedals that have a large platform like Look or SPD.
Speed comes from what you put behind you. - Judi Ketteler