What will fit?

 Yeah, using the dimension shown I get about 571 Sq.ft. Looks like there's about 18 feet of length in the shaded area, 9 feet by 9 feet ell ?  Do you want a narrow( close to the wall) benchwork with a point to point back and forth run or would you need to bump the ends out into the room for turn back curves? Depending on your era you'd need about 18 inch or larger radius curves so close to 4 feet of benchwork width at the ends to turn the trains around. Looks like there's enough room for a nice layout if you don't mind using some of the living space...DaveB

Some potential there

The space has a good deal of potential - could fit a nice layout if you used that space.

Where are the door(s) and what is the shaded space?

Wow, that's a lot of room.

Wow, that's a lot of room. Can you mark "North" and the 8' door so I have a better idea of the restrictions?

My entire layout would fit anywhere in there.

Plenty of room

That is plenty of room for a lot of railroad. If it were me and the view out that glass wall were good enough...I would adjust the height of the railroad in that area such that the view out of the window WAS my backdrop

I want continuous running,

I want continuous running, and can use the whole space except the shaded path, which should be about 3' wide. I think Dave understood it backwards.

Era would be 1944-1950 or so. Late steam no diesel, C&O based freelance. Not 18" curves for sure, probably 32". The layout can do more than stick out into the room, it can occupy the entire room eventually, but I'll want to build it in stages. Not TOMA per se, but get a piece running then another. Maybe start in the 'dining room' (the southern trapezoid space) and work 'north'. 

Jim: the doors are marked with the extra rectangles (that look like windows, but I was just using GIMP and couldn't figure out how to draw curves). The shaded path from one door to another needs to be kept open. Some access to the shaded area on the north wall needs to be preserved somehow. 

Dennis: North is toward the top of the diagram. It's not really north, I'm just using the directions conventionally. The sliding glass door is the one on the top of the diagram. The top wall is the glass one. the opening is in the center, roughly where marked.

Wabash Banks: Yeah, that's sort of what I was thinking, just plywood prairie along the north wall, single deck, so I can see out over top of the railroad, no backdrop. And maybe do that everywhere - I have no backdrop painting skills anyway. It's tempting to just do 30" flat tabletop all around, but it kinda clashes with the whole C&O hauling coal over the mountains thing. Maybe I'll have to call it the new river division, or just wave my hands a lot.

The view is great, it's a 9th story condo. So the walls are cement, and I'm thinking the layout should have legs instead of being bolted to the walls. The ceiling is suspended drywall on aluminum frame attached to the real cement ceiling, with recessed lights put in place for room lighting. I might have to add more spot lights.

I would build it around the walls in a continuous loop.

Put a swing gate of appropriate length in front of the sliding glass door.  Where the other 2 doors are I would make that part of the layout free standing with 48 inch clearance between the walls and the layout in the "shaded "L".  You then put in swing gates or lift ups as you wish for access at those doors.  Paint the walls light blue for a sky backdrop.  You might even put one gate in to be used for both doors in the "L".

"can use the whole

   Well that makes it a lot easier. I can picture lots of possible configurations for that space. For the C&O hauling coal I'd definitely build mountains, building them up against the backdrops.You don't need to be an artist to paint some basic blue sky. Freestanding benchwork with legs would make sense in a concrete walled building. It really comes down to how much time and money you want to spend on a layout. Simple design and theme can save both. How long do you plan to stay in the space and how many hours per week can you put into the project? Things like that are best considered before starting to build.Coming up with a  layout plan is actually the easy part.....DaveB   

stuff to ponder

How long - lets say 10-15 years? I'm in Mexico, as is this condo. I'm retired (early) just 59.5 years old. Maybe I'll stay here till I die, maybe bad health or something else will force me back to the US at some point, hard to predict.

How much time? Well, it's more a matter of energy. I don't know.  I suspect the energy will be in fits and starts, but no real limit on how much time I could put in on it. Just have to budget my copious free time between piddling on the layout and piddling on the computer, naps, and grocery shopping.

How much budget? I would want to keep a lid on spending per month, but wouldn't necessarily put an overall limit on it. If I keep at it, I could end up with a lot put into it. If I move, the layout's obviously a completely write-off. No problem there, it's my first non-teenage layout and is probably going to be chainsaw worthy despite my best efforts anyway.

What Russ said is I think pretty good. One gate to access the sliding door, one gate to access the middle of the layout from the 'L' aisle. lt is configuring the middle of the room, the aisles and peninsulas, I can't quite work out. One option is to defer that planning, by starting with an around the room 18" wide layout with a big hole in the middle. I could then have a big loop of continuous running going, and then after that figure out a plan for the middle of the room, but I'd really rather have a rough sketch about what I'm doing overall if possible, even if it doesn't get built exactly as planned later on.

I could also have an aisle around the outside on the left to the glass door, I'll draw up a pic of that tomorrow.

."I could then have a big

That would be a good approach. Pick an area of the C&O that you'd like to model and design an overall rough plan for the room. Once the design is roughed in  then construct an interesting portion of the overall plan, something that could be operated a bit perhaps by adding temporary staging or return loops to the ends.. If you choose a location in the mountains the curves out onto middle of the room peninsulas would look realistic like a railroad following the watershed up and over a summit. The first sections built could be test beds for benchwork and scenery building techniques. The more you build the easier it will become and the results will look better and better....DaveB