Hey Mad C, don't fret too much. My talents are pretty much entirely computer assisted. That script for Gimp from Rob A is the artist here, I'm just banging away.

Essentially, what you do is draw a black and white template of the map - outline the walls in one color and everything else is in the other. I use white for floors and black for walls, but that's not all that necessary. Once you have the black and white template, run the script that I linked to above and voila, pretty map. All I've really done is create a couple of brushes - one 5 pixel brush for creating walls and one larger, 27 pixel brush for doing bigger areas. I set the grid for 12 pixels and click on snap to grid. Add a transparent layer over the imported image from the pdf files and redraw the walls and whatnot, making sure everything snaps to grid. The first time took me a while, but, it seems to get easier as time goes on.

I then scale up my black and white template to 50 pixel=5 feet scale and then run the script. The first map, above, is blurry because I ran the script and then scaled up. Hopefully this next area - the area immedietely to the right of the entrance, will look better.