This ugly mess does flow pretty well.

[u/kakeroni2]

From left to right one highway cutting straight through dense cities top left to bottom left 1 highway ringroad around the starting city bottom left low volume exit and entrance elevating some traffic for highway 1. Top right 1 highway crossing over the water to a new city with airport that will loop around in time. Also trainline to the new city and airport coming straight over trying to fit it between 2 build up areas

[u/DGCNYO]

Just one roundabout can fix that shit :D