One person not a problem. I replaced my OEM pin box with a 5th Airborne by myself. Backed truck with tailgate down under pin box. Lowered trailer until pin box was about an inch above tailgate. Removed bolts letting pin box lower onto tailgate. Raised trailer so frame cleared pin box and moved pin box to the side. Moved new pin box under frame and lowered trailer until frame holes matched pin box holes with a little help from large screwdriver. Reinserted bolts.
OEM pin box can be lifted by one person once detached. Heavy but manageable. 5th Airborne pin box is heavier.