Yard dolly or trailer mover?

Anyone here use a yard dolly or trailer mover for their 5th wheel? Yeah, I know I've hinted around or asked before but didn't get much of a response. Before anyone googles it, I've looked at the Powermover, power caster, and other web sites ... I'm looking for actual experiences with these or other units, maybe homebuilt ideas?

5er is 8500# 25' on flat level concrete and I want to move it about 100'. The first part of the area is too narrow to maneuver the trailer into the turn with the truck.