As an owner of one of the first '06 Buddy 125's in Denver, I'll be following your escapades with great interest. As a daily commuter, the Buddy can't be beat. I've only put about 8000 miles on mine but never had a single issue. I'm not sure how many hours I could last on that soft saddle but, overall, the bike is pretty comfy if a little cramped.
I also notice that your route includes (or will be very close to) Utah 12. For my money, one of the most amazing stretches of road in the US. Good luck!