The best Guide you could get (or at least the best one I had when I visited Deadwood) is a little booklet put out by the Deadwood Visitors Bureau.
If you contact the Deadwood Visitors Bureau (3 Siever Street, Deadwood, SD 57732, 605-578-1102) they will provide you with guides that have maps and lists of gambling places, lodging, restarants, attractions, parking, events and more. You can also get some of this when you visit Deadwood at the History & Information Center, which I think was in the old RR station.
I thought I had a 800 number for this stuff, but can't find it right now. I may have seen it in some tour info source.
Don't forget to sit in a game of Blackjack at the Old Saloon No. 10. Hardwood sawdust covered floors, a real fun place.