Fred,
It sounds as if you have a great time ahead of you. That is the way to see this country is just take off and go wherever you want with no planned agenda. I never liked to go anywhere when it was planned out for so many hours or a day here and then to here. If I wasn't in such bad shape, I would be very tempted to buy a motorcycle and do just what you are going to do. Only I would be heading East and just kind of back and forth across the country. I would like to go back to the Grand Canyon and spend a week or so and other places where I never got to spend as much time as I liked. I would probably avoid going near Warren's as I don't want to get snowed in during a freak summer blizzard.
Ron