This screen printed map thing I'm doing is made up of 6 separations (Or rather it's going to be; 3 more to do) that are all drawn in pencil, straight onto thick tracing paper. I find it far easier to draw straight onto tracing paper than muck around with scanning in and printing back out on to transparencies. I've tried a few different tracing papers and find that the Goldline 112gsm A3 pads are a good option if you're not up for forking out squillions of quids.
These are the 6 separations I drew, then exposed directly onto the screens. I find it nearly impossible to not smudge graphite all over the paper while I'm drawing, but then I suppose I don't have the cleanest style of drawing anyway so I don't worry about that too much.