Important point. A tourist attraction and a military complex don't go together.

My thought was someone would wheel in a giant arch, say it's a gift for Trump, have him bring it into the main area of the White House, then people would jump out and overthrow the White House?

Call it the Arc de Troyomph?

It's clearly meant as an aid for a new Jan 6, no other reason to want to put an arms cache in the reach of a public mob near the white house.