Depends on launch location and what you have available...
If there's a courtesy dock
right by the ramp... a long line from a stern cleat to a cleat on the dock and a couple of bumpers on the side of the boat... loop the line over a bow cleat after the dock cleat and just haul it tot he dock by hand real quick. Tie and go park the tow vehicle + trailer.
That's about as fast as single handed unloading gets.
Generally single handed unloading is...
Undo all the straps, winch etc, but leave a line tied from cleat to trailer (knot that takes a quick yank to untie)
back up to where the stern is just getting light on the trailer...
shut off the tow vehicle.
hop into the boat, start it and back off the trailer.
get to courtesy dock and tie up quick.
Run to the tow vehicle and go park.
Go back to the boat and have fun on the lake.
Having lines already tied to the cleats for the docking helps make it a little faster.
Knowing how to do a quick cleat hitch is also helpful.
https://wlscjibsheet.files.wordpress.com/2015/06/cleat_hitch.gif