Thoughts on Roadschooling

Here's the setup. I have two wonderful daughters who are 9 and 12 years old. The older one is advanced and the younger is developmentally behind other kids her age. The younger one struggles to keep up with her class and information usually sails by her without her understanding it.

Although the school was great and the teachers dedicated, I didn't feel as if they could dedicate the time to her one-on-one to make sure she understands each lesson and in particular, math. She would come home every day and we would work with her until she went to bed in order to help her with her homework and understanding. She had zero free time; but she learned enough to advance and keep up with her classmates.

My wife and I have been very lucky to have started a successful business and sold it last year. We purchased a new King Aire MH with bunk beds and have decided to travel the US for the next two years and road school our children.

Why two years? Because it's important for me that my oldest daughter have the high school experience. I realize how important friends are to children as teenagers and I want them to experience the best our culture has to offer.

Here's where I'd like your opinions:

1) Am I crazy? Should I rethink the whole 2 year commitment? Can I stretch it to 3 years?
2) How do I keep them motivated and engaged while on the road?
3) Have any of you tried this?
4) Are there any "best practices" I should follow?
5) Anything I should avoid?
6) What are some areas of the country we should look at in order to decide where to eventually settle down?

I specifically did not post this in the "Family Camping" section because I'd like to hear from everyone, including those who would never consider family camping. So please let me know your thoughts.