I'm about to start GMing a fantasy campaign based around a countship. I did a similar thing some years ago, and for that campaign me and another player produced maps for the countship, every barony in it, every village and all the households for all nobels (the count, four barons and a bunch of knights). It added up to 20-30 maps (I'm really not sure how many exactly) and at least 100+ hours of work.

I'd like to do this again, but having a kid, a wife and a full time job nowadays doesn't leave me much time. Do you have any tips at all that could help me produce maps quickly with decent quality?

I'm pretty good at handdrawing maps, and I can do some things with GIMP. Unfortunately my attempts to draw maps completely in GIMP have proven very time consuming with poor results, so I'll probably just use it for finishing.