This is really looking good. ... Thanks for including your sketchy working out layer!
I have been wanting to try out a style a bit like this for a while... but my sketch method just does not lead to iso-mountains.... so I end up going back to top-down relief type views.

I can't see any bloopers in yours yet... except it is hard to tell the difference between roads and rivers, but the colouring will sort that right out :-)