If I'm right in thinking it's the had propelled hitch drive your thinking of, I would do just that, think but not buy.
They were hopeless at delivering grip and movement and you had to stand on the hitch to get traction.
I have a Motor mover ET hitch drive type mover, which I bought 20 years ago second hand for £250. I has served me well and has even been used on a twin axle van with reasonable success. You won't beat a fixed driver driving the caravan wheels for grip and power, but if you only need the mover at home or to move various trailers as I do a motor mover is a good alternative.