Mark:
Here is the amended version with minimum 42's.
I'm disappointed with my printer scanner. I don't know why the scanner is NOT picking up dotted lines. It is showing them as solid. I use the dotted to indicate a line is "hidden" from view. A lot of the passing siding is under Davis. There is sufficient space to access everything through the access hole. I don't know if you can kind of envision this set up because the main is constantly on a steep grade less the turnouts on the grade that are flat/level and the tracks connected to the turnouts are flat/level for at least one foot in all directions.
I also used dotted lines to show the aisle ways...it appears as solid on the scan.
Well here it is. Point to Point. About 50 to 55 feet of run--very good for a room this size. Three yard tracks and one turntable each town. Maximum four trains. 1 lane in each town should always be available. You need it to put the caboose on the correct end of the train for the return trip. Every time a train makes the journey, regardless of direction, the caboose will need to be put on the "new" end of the train--very prototypical.
Constructing this will require precise bench-work because there's just enough room to maintain a 36 inch aisle way in the area making it relatively easy for two people to pass by one another.
I really like this arrangement and theme. I've been checking out photos today. There is a hiking trail there now. You have great information to know how to make the scenery similar.