Most layouts have backdrops of some type or another. And most backdrops on layouts I've visited are permanent and immovable. Because they're often against the wall or actually on the wall, this often creates no inconveniences. But I've seen backdrops adjacent to aisles with lack of back access and other layouts whose backdrops were cumbersome to remove for access to the layout, and others that had holes cut in them for a crude and limited access. I resolved to have better access on the layout I built—the Deep Rock Railroad—soon after going on a particular layout tour where the above situations were observed.

I attach Walthers 2-foot x 3-foot scenes as directed with spray adhesive (3M Super 77 works well) onto 1/8" hardboard. And then I use one of two methods to make my backdrops removable:
Removable Backdrops
this layout has easily removable backdrops
aluminum bars support backdrops (rear)