Sketch as promised.
Taking your ideas, it would mean that the door is on the lower left hand side. Each grid is approx 750mm or 2'6" (in old money) square. It's not even remotely to scale trackwise, nor is it prototypical, but it's a first draft to give an indication of what's realistic.
Track parallel to the baseboard edge always looks odd, and in an irish context, if the track is straight as the crow flies, it's bumpy as hell on the horizontal and vice versa, so never ever have it straight. The slightest curve - say 4 inches, over 4 foot, looks great against 4 foot of dead straight rail.
All routes, no matter how mundane, should look natural on their own. If you can avoid small radius points, all the better.
I've included a dummy line to the south. It could end in a tunnel going to nowhere, but it's a great spot to pose stock for photos.
I've also included a similar line from the freight/goods area that would run around to a lower level fiddle yard, as Dave has proposed. I'm sure the track can be rationalised so it's not a shunting puzzle to get stock up from beneath.
The only unnatural curve is the one for the lift out section. Bridges can be unnatural curves too, so consider a mini viaduct as a drop in section. I'm sure someone around here could make an MDF segment that would fit perfectly. Name escapes me though....
I'd keep the baseboard width to a maximum of 3 feet, less if you don't like reaching for fallen stock.
Richie.