Hi!
For the colours, I would suggest you try some thick colours for the lines/borders, and then go progressively but quickly in subtle tone. Look at some maps on this website I found:L http://joxanet.tk/cise/historical-at...-east-1712.php
Some of the maps use solide colours all long, but some, like the one on ancient middle east, use thick colours for borders then light and highly transparent in the inside.
Its easier for the eye to look at some contrast than simply looking at a map full of solide colours.
By the way, do you study in archaeology? Cause I do as well!