Periodically, I need to move a large sheet of plywood or a door into the garage or shop. As I age the weight and size are too much for me to handle safely.
My solution was to make a 3 wheel dolly so I can move them long distance and through narrow doorways. I used a 1x12x20 pine board for the base. Trim boards (1x2) were placed on two sides to form an L to allow both forward moving and turning on side to roll through a narrow door. A 2x4 I beam was used to hold the axil far enough from the base to prevent the lawn mower wheels from rubbing on base (see image). A 2" caster was added to allow the dolly to be turned for narrow doorways.
Door dolly is attached to the door or sheet of plywood with 2 C clamps. Dolly is rolled into the truck using wood ramps.
View showing trim boards and caster placement.
View showing I beam and wheel placement.
Thoughts and Hacks
Tighten the clamps otherwise dolly will slip off the door.
Pull dolly on rough ground.
Rock door when going over a bump.