Gotcha. A few places come to mind that may fit the bill.
•SSE of Tall Town, which has some nice mountains there and ocean front to the east.
•N of the main city and right past where I live. There's a good mtn stretch there and access to water on both sides.
•Where the old Southlantis line ends now. It's reformed with new terrain and if you don't mind some terraforming could be really nice.
I'd be happy to fly over to all these places with you nest time you're ingame.