Travelling across the good ole USA

I would leave mid August when most kids are headed back to school, crowds are thinning, and most campgrounds in the north are still open for another two months. You will probably need reservations for Labor Day weekend but other than that you should be able to wing it. Head west on the northern route making sure you pick up the Badlands and all the sights there. Once you have seen your son head over to the Oregon coast and hug it going south through the Redwoods in CA. I would then head toward the Grand Canyon and tour the Utah national parks and head home. That is assuming you have not been anywhere in the west and want a sampler tour. To that I would suggest you add any and all national parks and sights along the way that interest you. There are a gazillion places you could go with unlimited time. Have fun!