Help establishing a route from PA to warm south west in Jan

I assume you are familiar with
www.militarycampgrounds.us
they have all the info on those along the way.
I'd just hop from base to base in one direction with some boondocking in the long gaps between bases. The other direction hit the parks you miss otherwise. RGV, Big Bend etc. There are enough bases to make use of to avoid some of the problems most experience with not being able to find a park for basing out of to tour an area.