I second the idea of a hitch receiver setup. It just makes your winch a lot more versatile, being able to move it from truck (front or rear) and trailer to trailer.
I didn't have a lot of room at the front of my carhauler, so am set up with two receivers, one vertical at the front edge of the bed to hold the post with the horizontal receiver at the top, to which the winch is mounted.
On the gooseneck, there are two crosspieces of 3" channel-iron bridging the two upright pieces of the main frame where they come up vertically. A piece of 1/2" plate welded between those cross pieces and a receiver then welded into the plate.