We stayed at Arizona Charlies CG on Boulder Hwy, secure, and clean showers/RR's, We were there on 5/2015.
Many of the casino's have Truck/RV parking, in their parking lots out behind the casino's! A call ahead would be prudent! If you want to show up, follow the signs for delivery's, or big RV's or truck parking, or go where you see other MH's and trucks, and security will let you know, and show you where to park, if they have a certain area, and most of the time keep a watch on your rig for you! Avoid the car/valet area's! Most have clear sign's that will tell you where to park, and if you get into a spot where you are not comfortable with, stop, turn on your 4-ways, and security will show up quickly! All Casino's have good security systems and camera's!
I delivered slot machines to casino's all over the country, in a big semi-truck-trailer before I retired, and have found a few that were not truck/RV friendly, but not that many!
A lot of the big casinos on the Las Vegas Strip, do not have the room for RV's or trucks for that matter!
Retired, and "Always on Holiday!"
1996 Monaco Windsor 38' "Mona" 275 HP., 8.3 Cummins, 3060 Allison 6 speed