All federal recreation areas within designated geographical lines of the border are now required to post notices of potential border crosser. Many portions of this "wall" are actually far less imposing than what you see on TV.
Do not confuse the public released images of some massive solid structure with the reality of what is actually being build away from public eyes. Additionally, don't let fear mongering dictate where you go less you miss a whole lot of this country. You have a greater chance of being killed on the streets of Dallas than you do coming in contact with an illegal while boondocking for a year along the border.