It sounds like you care a lot about things being canon but if you don't, you could do a lot worse than downloading the Pool of Radiance SSI game for the commodore or Apple and checking the documentation. Alternately, you could download the coversion for Neverwinter Nights, open the various areas up in the toolkit, take screenshots (control+printscreen) and then stitch them together in photoshop or printshop. You'd end up with a very nice-looking map even if it weren't 100% canon.