@sockknitter I just did a quick test on the map, and I don't encounter your problem. All the highways connect. The unlock all tiles mod I have listed is unlocked via milestones, and you have to buy them still. That is probably an issue with your roads. Link a screenshot here so that I can see exactly what is going on.

Hi, I like the map lots, however, the main highway connection is towards the very bottom south west corner which doesn't link to the "workable" map tiles. I have the unlock tiles mod installed and it does not unlock more than 9 tiles. The "please connect your highway so people can move in" flashing at me the whole time I was building and there's NOTHING i can do, it's very frustrating. I've spent many, many hours with this map and I think now I have abandon ship to start somewhere else :-(((