Just my opinion, of course, but I'd be inclined to:
1. Use what you have in HO, and
2. Design a point-to-point adding on later until you actually have a large continuous-run mainline, made of additional doors or other, narrower shelves around the garage. (Of course, you would have to measure the chances of that overall plan being a success).
Until my garage was ultimately turned into a family room, I was building such a layout on 2 x 6 foot modules, and quite a bit of scenery and HO railroading can be done this way. Backdrops and background flat buildings can expand narrow shelves into what appear to be much larger scenes, and one or more of the corner areas could provide a good place for the mountains you refer to.
Good luck!
Okay gang, here is my question.
I have decided on my era, and my road (obviously by my title) but now comes the decision. I have limited space (half of my garage) and I have two "doormanoes" to work with. so that means I have two choices... a point to point of 2 foot x 13 foot (6.5 foot doors), or 4x6.5
THe 4x6.5 provides the best continuous run options, and I can model two locations, one on each side of a mountain pass center (nice separator) but... My end goal is to have a room where I can run additional doors to give myself a modular run...
So do I build a continuous run now, then scrap everything for my modular later? Or do I build in the mainlines for modular into the design??
And as a second question... I have two trains and cars in HO, but I am tempted to run N instead (assuming I can find what I need - or paint it myself) thoughts?