The least amount of action as far as turnouts and such seems to be on the trackage in the lower left hand corner of the layout. You could try putting your Main Street above the mainline curve but not over the yard lead. The tunnel portals would be halfway through the mainline curve and about where the yard lead diverts to a spur. You could use a cut stone wall or a cliff at the edge of the elevated town so that the yard lead would run along the walls edge. A simple highway bridge over the yard lead would be your exit out of town so it doesn’t just turn into a dead end. Looks to be enough room where structures could be on both sides of the street. You may have to cut some access holes in your wood roadbed for a just in case derailment inside the tunnel. A tall structure could be used to hide the fact that the town or street goes up against a wall and aid as a view block. I know you have another tunnel planned and this may not be a good idea to have to much hidden trackage.
I just don’t think you have enough room along your yard area leading to the turntable. You would need to face the building fronts toward the aisle and not have room for the street. You could always leave the street out and just model the sidewalk. Still it looks like a busy area and you don’t want to have to reach over structures for anything. Nor do you want to limit yourself to have just 1 or 2 story ones.
The yard lead has a nice open area on the curve. The use of a curved switch would create a nice spur for something like an fuel dealer.