Going up the hills was predictably difficult; I learned that you can simply stop and catch your breath without dismounting.
Going downhill was a blast, I hit 53.5 mph at my fastest. I'm still getting used to the feel of the vehicle and when going over 40 mph there was some apparent cross-wind action that made me nervous, but I'm guessing that's just one of those things you have to get used to in a new ride.
I still need to work on dialing-in the fit. I'm still bumping knees, toes and heels a bit.