Don't laugh at my setup...lol.
I had this 1500# winch in the shop for a electric snow plow. So I bolted it to a pintle hook mount to see if it would pull a car. The mount weighs as much as the little winch. It can hold a much larger winch.
Stuck it in the receiver in the front bed of my trailer and it was plenty to pull a car onto the trailer, even better when I used a snatch block(2 lines)
I have done a lot of trailering and light weight is very important to me.
I stick this little setup in one of the storage doors on my RV and would use it if my car ever broke down and I couldn't drive it on. Works for me.
Wiring? Don't look at me, I drag a battery out of my RV and use alligator clips and the handheld switch that came with the winch.
Careful not to overload your tires with heavy equipment on your trailer.
It will tear the teeth up in the winch, don't ask me how I know 
I now make sure and back the winch up until the winch cable is laying on the floor of the trailer after I tie the car down with the four 5000 lb tie downs, one on each corner 
you will need to retighten the tie downs after thirty to fifty miles, the nylon straps will take a set and get a little looser 