Hello there. I'm a long-time fan of the series. Your enthusiasm really brings me back memories... I only started playing NFSW right after the Lamborghini Murcielago update in 2011, when things started going downhill for free players. I'm the one who did Unlock All Tracks V3 mod for the offline server - I wonder if are there people here who still use them? Lost my interest as well, and it looks like no-one bothered to develop an alternative to NFSW, another free-to-play, free roam world street racing game.
So I like your idea. It's hard work and I'm sure it could take years for you to even get to the UC map. As some people here say, you may get in trouble even just for using same cities. But at least that shouldn't be such a big worry. All of the cities in these series are loosely based on elements of real-life cities in North America.
If I can help you in any way, that could be geography and track designing. Being unsatisfied with how few tracks there are in NFSW, I made a blog with my own possible track variations. So I could do more variations for Bayview too - and Olympic City, if you also try to model the streets which are not used by any track, so the devs didn't develop them at the time (hence no free roam - sadly, the drag tracks were also designed without taking this into account, they don't really fit on the map). Tri-City Bay already has many, almost all possible variations.
Wait, you are not planning free roam in between cities yet, right? It would have been interesting - and not impossible - to reconnect Rockport and Palmont in a different way. The problem might be how big the map can be used without affecting the whole game. But if it can be solved, there can be bigger distance between Rockport and Palmont (in between them there were canyons, but they made shorter connection roads for obvious reasons), so you could put canyons and San Juan too there. I know, just dreaming with eyes wide open right now.
If or when you will need more imaginative/realistic names for reverse tracks or want more fancy alternative track ideas, I can give a helping hand. Ok, now I'll try to run your build... Wish you all the best. :)