Hi Will,

This example is of a similar style, but done on paper (with dip pen and watercolor) in 3 days. A digital version would be smoother; is this the sort of style you're looking for?

The way the map is drawn, what I could have by the 4th would be a basic sketch of the entire map with a smaller section done in detail; would that work for your client?

Good luck in finding an artist, whether my example works or not! What a great project.