A rethink of my n gauge layouts.

[NScaleNotes]

I don't know if this is what you want to hear but based on the criteria you stated I'm not sure this is the right track plan for you.

Whichever side of the layout you stand on you've not really left yourself much 'eye-room' to actually watch the trains go by, you might be catching glimpses of them between the trees and the very big station and before they head into the tunnels (which can work if that's what you like) but otherwise you won't be seeing them much.

You've got a lot of space for scenery but in my mind 'Mt. Traverser' is going to block the view of most of your work if you stand on that side of the layout. In some ways it might be easier to incorporate a backscene down the centre of the layout rather than a giant hill right up against the station. At least you can put low relief buildings against a backscene and suggest a larger town behind. This would also mean you always have easy access to the fiddle yard/traverser as you wouldn't have to cover it.

Take a look at this:
This is by a guy called John Leader, I remember it from the Jan/Feb 2011 issue (#63) of N Scale Railroading Magazine. Very simple track plan, loads of space to watch the trains and make scenery, you'd just have to slightly alter things if you really want to incorporate a traverser.

Like others say, perhaps put the station on a curve and just model half or even a quarter of the station with a bridge as a break, platforms are boring and it leaves much more room for running trains through interesting scenery.

[NScaleNotes]

Plus if you've got the room, you could always create a junction in one of the corners and put the traverser off to the side.
If you made the traverser free standing you could run with just the loop or plug the traverser in when you want more variation.

I'll stop now 

[Ditape]

The plan as it stands fits my available space and makes use of my stock pile of Kato unitrack.

[longbow]

A conventional fiddle yard with anything like the capacity of the traverser would swallow too much length. So I'd suggest a couple of fiddle yard loops supplemented by cassettes.