Want to build one of these.......but motorized

I'd like to be able to manipulate my trailer without having to use my truck. I park it next to the house and continually backing the truck to it to hook/unhook is going to take its toll on the yard. I was thinking of building one similar to the pic to utilize maybe an atv winch minus the rope of course. Either weld a sprocket in the center of the drum and put one on the axle of the dolly and use a chain or incorporate a ribbed belt(think blower belt). Then have a button on each handle you could operate with your thumb as you are steering it into place, one forward, one reverse. Since it will only be used for 5 minutes at a time max I'm thinking a lawnmower/motorcycle battery would be ok vs something bigger. Mine would likely need a third tire that will pivot 360* where the leg at the back is since my trailer is rather stout. What say you B2B'ers?