Scott,
Since you are building right against two walls, I see several areas that are going to be "maintenance" headaches. The first is your yard and the top half of the sweeping curve around it. Track cleaning, repair and derailment fixing will require you to crawl on top of the layout, but your terminal structure location will make that difficult. The second troublesome area is all the track near the tunnel under your second station where the same problems will crop up although with apparently less interference for crawling on top of the layout.
Operation wise, your yard is nowhere as large as it seems because your longest track is cut in half by providing access to your third terminal track. And, using another terminal track as a switchback to your industrial area both makes the switching harder and lessens the usefulness of the terminal.
Finally, you don't say what era you are modeling, but whether steam or diesel or electric, your plan excludes engine service facilities. Beside providing more realism, they also provide some switching opportunities both for supplies and parts and for just swapping locos to run on the mainline.
Just my thoughts.
Chuck
