Another option might be to install footman loops on the TC edges to attach a tarp.
Mine are set up to use the bungee balls to attach to the grommets of the tarp and then a couple of tent poles and guide lines to finish. I have loops mounted along each side and the back. I added a few 1/2 inch grommets to the tarp to match all combinations.
I have a pop up TC so I can use my portable steps or crank the top down to reach and install.
If the loops were too high for me to reach, I would probably fashion double S hooks from coat hangar wire that would allow me to connect and un-connect the tarp grommets to the loops with my portable grab stick.
If I had a door clearance problem, I think I would fashion an arbor from pvc pipe, fiberglass pole or aluminum tubing that would raise the tarp above the travel of the top of the door. it could be mounted to the wall, jacks or free standing a few feet from the back wall.
Just thinkin' out loud.
Hope this helps,