If you're going to walk across country to visit friends, why not use the roads? You'll find that there will be large stretches of territory that are not woods or wilderness nor public land for you to use.

I personally recommend motorcycle camping for this sort of experience. Still somewhat rugged but you get there a LOT faster :-) (I did this very thing to celebrate the end of my Navy career.)

The cross-country walkers I've heard about always have some kind of support crew to bring along food/water and moleskin.

Why not try a 50 mile 3 day weekend and see how it goes before you commit to this?