We have been RVing about six months of the year for about eight years now and put ~170,000 miles on the RV. We have been from Upper New York to Key West to san Diego to Seattle... and everywhere in between. I cannot think any specific place that I would recommend over any other... maybe after a few more years I can make that judgement.
I can recommend one of my favorite Blog, however, that may help you get started. Life on the Open Road
Diane, although she has a trailer, is doing what you describe full-time. Go back through her Archives and you will be very pleased with the descriptions of her trips -- particularly interesting (to me) are any of those in the Western U.S.
In addition, there are a (large) number of RV related sites listed in this Forum in several places
Like everyone above says, it doesn't matter what you do, you will have the time of your life.