hi there absinthe, very nice first map.. and so much better than a blob ... I'd make those roads a lot smaller, if they shall fit the look of the map. No wider than your thinnest river ... I don't no GIMP but a negative bevel of 0 can help putting the road in place. The city icons could use a little strengthening, they are a bit blurry - try making them with just a hard brush, that should work.
And I have to try on my new Morningstar of rather nice repping +5 - so have some