How to keep winch cable from bunching up on one side

How about mounting the winch onto a plate with the right size ball on it, then pull out the cable to the anchor point. It would be quite easy to swing the winch from side to side to get it to spool properly. Most likely, the spooling would just occur naturally as the plate would swing a bit on the ball.

Set it up so the incoming winch wire is directly in line with the ball and just run an electrical cord out to the winch. After you pull it up, lift your trailer hitch and release the winch.