Update:
I rode 20+ miles of trail at Talladega National Forest this weekend. The hilly terrain was rough, but FUN!!
It was awesome to be able to cover a 5 mile long section of closed-off road (10 miles round trip) in just a 2 hours, despite some pretty steep hills. It wore me out, but it was much better than walking. I was able to just walk up the stuff I couldn't pedal through, and then enjoy cruising downhill at mach 5. I found some good looking spots, and saw 8 deer and 1 hog over the weekend.
I will absolutely be bumping up my lower body training though. Just two weeks of riding has already toughened me up to the point that local (flat) stuff doesn't scare me, but I'd like to know that I can tackle the hillier terrain further north.
Plus, this stuff is surprisingly fun! I can see another, nicer bike in my future, as well as some vacations to rougher terrain. I've got a 4 day weekend coming up, and I intend to try and cover all the roads on the local WMA.
Overall, I'm happy with my decision to try a bike again. I am thinking less and less about going electric at some point, since I now am sure that with a little training I can cover any terrain the state throws at me.