Dave
I don't know if my problem is applicable to yours but here was my solution which was never completed as regards decoration by artist or wall paper. But still can be.
I had 13" of kneewall space from layout to rafter wall. I had railpower on and trains running and some structures in place before I realized that i needed to consider the backdrop if at all. I ripped 1/8" x 8' Masonite and velcroed it to the kneewall space with the thought of later taking it off for an Artist's treatment or paste up scenes. I did not permanently fasten or light wire any structures with that thought in mind. Unfortunately 7 years ago health issues intervened and I never followed up. Anyway the poor photos below show what I did with the velcro method.
Below corner section and first 8 ' section already installed, second section on quilt, prepared for installation including where kneewall door casing (taped over) was removed.
Opposite side using some white Velcro
Below you can see the horizontal line of the panels in this corner photo. Structures including coal pile,stack, track and structures are still removable.
