More questions than answers on my end, I'm afraid ...
Where does the mainline go on the bottom/right of your 3rd pic? Are you planning on building directly on the ply/board, or might you consider building up on foam with some topagraphy contours? If the latter (hint, hint!), I think your little tourist town would look great with a small river flowing through/near it, with a small trestle bridge on your trolley line. Something to break the basic flat-loop look.
Your little tourist main street reminds me of the real-life one at Clark's Trading Post in NH:
Maybe some ideas from that?