I found this great road and street map of Nevada in 1947 at this year's convention. Here's a piece of it that shows the downtown area. Notice it was not acceptable to advertise yourself as a casino in those days. You were a hotel (as the Last Frontier and Sal Sagev were) or a Club as Monte Carlo and Las Vegas Clubs were. Gaming was mentioned in the advertising though.

This is a big scan so I didn't imbed it in the post in consideration of the load time for those using dial-up connections. Click on the link if you want to see this 200K map.

http://www.chipguide.com/tcbuploads.php?image=LasVegas1947MapDowntown.jpg