Michael,
I did a lot of research on this forum and sought the same feedback you are seeking now. These were the things that were passed on to me...
Don't think now... Think 10-15 years from now when you are older and not as mobile.
Can you physically reach everything on your layout from a standing position?
Do you want to crawl on the floor under the layout to get to access hatches?
You have a 13x16 grid. Is this the size of the room or just the size of the layout? Can you walk around it? If not, how to do plan to get from the open area on the bottom to the open area on the top?
Bob (RSJB18) above recommended you consider the height when working on top. Also consider the height when working on the bottom. I'm 6'4", so when I need to sit on the floor to work on any wiring for anything, the layout is tall enough so I don't have to crouch and I won't hit my head on anything.
I don't want to derail your plans "pun intended", but you may also want to consider an around the room layout with a lift bridge from wherever you enter the room. That will put you in the middle and give you access to everything. It will also make all of your building and scenery easy to install, clean and refresh.
My first layout was a large platform for the kids when they were tots. When my son was 11 we tore down the platform and started building our around the room layout. That was 6 years ago. I'm 52 now and very happy that I do not have to worry about accessibility. I'm sure I'll be even happier at 62.
Just some things to consider.
Have Fun!
Ron
