Good gosh,
First the op question, and then 3 pages discussing logistics.
"At this point in time Mr. Trump couldn't build a wall around one of his privately owned properties with his own money."
The GD POS Dems would sick an army of lawyers on him, along with traders/traitors in multiple government offices.
Fixed
How the frick would they stop him? We got barriers, ports of entry/ exit on interstates all over the Southwest US already...He declares an emergency, he could do whats necessary to protect the US and control drug trafficking and immigration... They could try to stop him, but screw them...
You got a better solution? Building a wall on a border in remote areas that are hard to access isnt feasible....
