The logistics of securing the border are not the issue.
LOL! You're at over 30,000 personnel in forward deployment, with 1 mile gaps between men. You think that will be sufficient?
You've also left out support crews, bases, detention facilities, roads, infrastructure, etc. Realistically you're looking at a few hundred thousand men to seal just the Mexican border. You are talking about tens of billions of dollars annually. Not going to happen, and it doesn't need to. Consider an asymmetric approach.
LOL!