Find an old-unused tabletop. We had one tucked away in storage, but you could easily find one at a Restore or Garage Sale.
Using a chalk line, snap lines lengthwise, cutting the board in quarters. Evenly space out the roller ball transfer bearings. This board could be used as a furniture mover as well, so placement throughout the entire board would be needed to distribute the weight. I used 4 inch spaces on the sides, and general center spacing in the middle. Screw roller ball transfer bearings into place.
Mark and cutout the outlet placement. Run the wiring underneath and using wire clamps to run it and keep it out of the way of the roller ball transfer bearings.
Just for safe measure, since the board is going to be very close to the ground, I wrapped the outlet with electrical tape, and then a silicone to cover the wiring.