Around the wall layout, attached to the wall?

Yes, for around the wall railroads, you can attach the layout to the wall.  However, if you plan to move soon, or plan to change things around ever, making a independent  sectional layout that happens to fit around the walls of the room might be a better option.  If that is not the case, then building a layout that is bracketed to the wall will work fine, and will simplify the bench work that would normally be needed for stability.

If that is the plan, then screw or bolt the bench work  at each stud for  stability.  Studs in modern homes are normally 16" apart on center.

I built this 3'x 12' semi-permanent shelf layout with no anchors into the walls. It is all supported on simple 2x4 framework at the ends and the whole structure is wedged between the end walls. The framework also supports a long storage shelf above. This setup will easier to move in the future if/when necessary. The general idea might be useful for part of an around-the-room layout framework.

I have a 20 x 20 family room, but I can't set up a permanent layout because the room is used for other reasons on occasion. My 2 x 6 modules are freestanding and supported by 1 x 4's that are simply notched and tie the units together (drywall screws hold the legs to the modules).

I could anchor the modules to the walls with a few screws, but the room is painted- the last thing I want to see is screw holes when the layout is removed. The modules when joined together wedge between the walls and are pretty stable for the most part.

Geno

I attached the layout to the walls and used leveling screws on the legs so to level the layout as needed.

I painted the "sky" backdrop before building the layout. Also put lights under the layout.