Who says I can't change it again? Shucks, when I finally get out there, I'll probably still be making modifications as I go.
I have started working on an itinerary, and it looks like 11-12 days is really cutting things close, so I expanded the time frame up to 14 days plus two extra weekend days. I also am thinking of substituting air travel for certain far west parts of the trip (e.g., Albuquerque to Phoenix is $128/round trip via US Airways, including taxes) but maintaining road travel for other parts. Otherwise, I’m looking at around 55-60 percent of the total 16 days spent actually doing stuff, with the rest devoted to travel and one spare day.
Have fun with it. It’s all about the adventure. I was never one to get too hung up on planning a trip like it’s some kind of military campaign or something. The most unpleasant trips were the ones where I tried to travel too far and do too many things, and never really just took the time to relax and enjoy it all.