Good idea, I did something like this on my layout, some scenery pieces are actually fixed with screws and thus easy removable, also the electric connections are made with plugs. I think this is good for maintenance and if you have to move the layout to another place.
Yes, that is a neat idea. The mountaintops are removable on my layout so that we can move it someday and I did as you using plugs for wiring connections between the two tables. It takes longer to engineer these features, but are worth it in view of the many years it can take to build a layout.
Yes, it works quite well: If you have the space to store the modules. Couple years ago on my N Scale layout I started that but ran out of storage space. I did bring along quite a bit of my foam mountains scenery modules that I can use in my HO layout. I had to break them up to fit into cartons. I had plans to make cities the same size as mountains and create a 'metropolis' where there was a mountain range. On the future layout there are at least 4 places where I will swap out mountains for towns or seasons.
