Yes, you could use a cordless, I plan to give it a try. It uses a square drive shaft but I believe you could use one of the universal sockets or make one to spin the drive. The manufacturer sells an adapter for $40 but that's crazy.
Here's a daytime photo of our trailer and the incline of our driveway...the trailer is level. I believe the manufacturer says a 5 degree angle is acceptable, mine is more and it functions quite well.
Thankyou for the picture. As they say a picture is worth a thousand words . I don 't think that would work for my situation . Too much hill to push up for me and I would have to make a turn from another hill . I am always looking . Pat