Uh oh forgot backdrop....

We used Masonite attached to the wall with Velcro. It has done fine. You might want to put the weight on the layout which should reduce the amount of Velcro needed.

Good luck.

I'm mounting mine on a sheet of Formica, then I'll attach that to the wall.  I'd certainly move the layout out of the way to mount it, it'll be way more difficult without that step.  Here's my freight yard, that's where the backup goes.  I can move the whole works by removing the four lag screws that secures it to the wall.

Here's a mock-up of how it'll look with the backdrop installed.

I’ve done this with building flats. They sell magnets with countersunk holes. Screw them into your wall studs. One in each stud should be sufficient. They have to be pretty close to the same height.  Then glue a strip of thin metal to the backside of a Masonite sheet at the height of your magnet placement. Glue on your backdrop. The fact that you left a 1/4 gap should be about right with the magnet and Masonite thickness. Just put the backdrops up  and the magnets should easily hold them.
When you move. The only damage to the wall should be a few screw holes to putty over.

Very good.  Recommendations for cement to glue the backdrop to the Masonite?  Also I went to cut some masonite the other day with my saber saw.  Wild stuff to cut....but we got through it.  Magnets on Amazon?  Any specifics?

This may be heresy, but given that it is going to be a short term layout do you really need a backdrop?  If the answer is "yes" then how tall and how good do you need it to be?  When the time comes to move, you probably won't be taking your backdrop with you.  So why not just roll the wall with some light blue paint and then mount building flats on some low quarter inch board that can slide in to that quarter inch gap you left between the layout and wall.

Just hang it like a curtain.

See how here:

https://ogrforum.com/...15#74495642682553715

I think these are the ones I bought from K&J Magnetics. They are plenty strong. 1/8 thick and if you have a laser level. Easy to install. Home Depot should have metal strips that are thin. If you could measure fairly close. Even a thin fender washer would work glued to the Masonite. The key is to use a good glue for the metal to Masonite bond. When you pull off the back drop when the time comes or have to adjust it on the initial install. You want the metal strip to stay in place.

Make sure that the metal strips are steel or iron, magnets will not attract/hold aluminum.

I agree with @Avanti that you can simply hang the large cloud sheets like a curtain. Instead of furring strips, I just use thumb tacks into the drywall.

For the smaller scenery backdrops, typically 13" x 36", mount the sheets to the back of a foam board (usually 3/16" width) and insert from under your table through the 1/4" opening. You can use wood shims to hold the board/backdrop in place.

Using these two methods, you will have absolutely no damage to your wall.

All excellent and thoughtful suggestions.  Very much appreciated.

I do like the no backdrop or curtain options as we have had our fill of crime and congestion in Colorado Springs and are ready to move on to less chaos.

Magnets also seem a nice option.  Much appreciated.

Rest the weight of the backdrop on the layout, then get some “sticky tac” from your local art store and stick it to the wall. Teachers use it to put posters and stuff on their walls, and it peels right off without affecting the wall.