I tried to map Deathtrap Dungeon when I was a boy and I'm pretty sure I got everything wrong, not least because every turn I took seemed to result in a quick death. Reddit user Qatlas, though, makes it look easy.
Handsomely-drawn maps include Firetop Mountain, the Forest of Doom (pictured above), Deathtrap Dungeon, City of Thieves, the House of Hell, and various other places from the U.K. gamebook series; prints are available at their website. I like how the "contemporary ye olde" style seems oddly suggestive of modern tourist placards you might expect to find outside Yaztromo's Tower or Port Blacksand were they real places.
New editions of the books themselves, including the original art, are on their way from Ian Livingstone and the Jackson Steves.