Enlarge your idea of a wall......all areas will not support “a wall”....there are already high and large slated barriers, (BTW what the border patrols requested) going up....the work has been going on for awhile now. But what will be used will depend on the ground, terrain and where it's going.
Trump is in a bind. He has promised his low information voters a wall. While there are areas where that is useful, it does not affect the problem that at border crossings only one in five cars is searched, or that significant amounts of drugs and possibly people are entering the US through tunnels. The Wall won’t fix those problems. If he has not already done so then he needs to educate himself and his voters about the complexity of the problem. Yes, short answers are easy, but this issue is beyond the easy fix.