If they updated El Capitan and made it four to five times longer, I think it would be awesome. A long track doesn't necessarily have to be an existing track just as long as it is has excellent scenery. Base something off of Skyline Drive in VA during autumn or a blast through the Swiss Alps during summer. Southern France, Jejudo, Korea (AWESOME place), some twisty coast line, etc. It doesn't have to be exact, just a thought of "What would it be like if there was a road to drive through here?"
... Isle of Man would be awesome too.