Matt, Congratulations on your new house and space available for a nice sized layout!! My only suggestion is that if you have one turn-back loop, you should have a second one to turn-back the other way. It could be done as a mirror image of the first turn-back with a switch as you exit the inner loop upper tunnel portal.
As you may be aware, there are others here who can really pick it apart with some other great suggestions I would never think of.
