Thanks for all the advice!
I think I need to raise my seat a couple inches for the bike to fit me better, but other than that I really like the bike.
I think that the best thing for me to do right now is to get a cycling computer so I can keep better track of how far I'm actually cycling. That would let me bike really varied routes while making sure that I was keeping up the distance I wanted. Past that, I think I'm ready to add some hills.
Thanks again.
-Nick