I do all my drawings in StarOffice/OpenOffice.org. Nearly all my drawings are for software, so surface lines aren't a big concern for me. But, I can help you get your drawings into some other drawing program that might make that part easier.
I'd get your CAD drawings as close/complete as possible. Then, export to TIFF or some other common image format.
Then, in OpenOffice.org (OOo), create a new drawing (or may a new slide in your drawings) and import the graphics file there. You can make it a separate layer if you like.
Then, I'd have some canned surface lines lying around (more about making those below). I'd copy them, paste them on top of the image, and drag them around until I liked how they looked. I'd repeat the paste and drag (incl. rotation and resizing) until I was satisfied with the whole drawing.
I don't have any surface lines in front of me, but I'm imagining a set of parallel lines, each of which is dashed. The center dash would be more than half the entire length and there would be two short dashes on either end.
I'd make a single dashed line by drawing the dashes as individual horizontal lines that I'd center horizontally (to align them) and manually space them relative to one another. Then, I'd select them all and group them. Then, I'd replicate the group two times, making them stacked vertically in parallel. I'd shrink the middle one and shrink the bottom one even more. Then, I'd group the whole bunch. There, a surface line cluster.
That surface line cluster could be copied, pasted, dragged, resized, and rotated as necessary to make my drawing. I'd also save the surface line cluster in a separate OOo drawing for re-use in other drawings.
Would it look great? Don't know. But it would most likely suffice.
Regards.
P.S. In fact, with modest prodding, I'd probably try to make one of those during a break today and post it here or somewhere. I have a bracket for OOo drawings I'd be happy to share, too.