If you want to listen to about 85% of the traffic, program in 853.9000 as your control channel. You will need to put your scanner into control channel trunking only mode you will also have to select custom band plan and entered in the rebanded information (below if needed).
Are you using software or doing this by hand?
If you are doing this by hand and are not already aware, here is the custom band plan information you will need to enter into your scanner. If you are already aware then ignore this, however someone else may find it useful:
Band Plan Base Freq (Lower) Base Freq (Upper) Offset Polarity Spacing
1 851.0250MHz 854.0000MHz 440 + 25 kHz
2 851.0125MHz 868.9875MHz 0 + 25 kHz
Good luck and happy scanning in Vegas. The talk group id's that you may be interested in listening to can be found in the Radio Reference Database, otherwise put your scanner into talk group id search mode and listen in on all the traffic.
Are you sure about that frequency 853.900?
Didn't see that as one of the frequencies
actually doing a search for that freq in the whole Nevada comes up blank
EDIT:
JUST did an FCC search and came up with this:
FCC Licenses for 853.900 in the State of Nevada
Licensee Frequency Callsign Stat City County Svc
Southern Nevada Area Communications Council 853.90000000 WQLV227 A Las Vegas CLARK YE
Southern Nevada Area Communications Council 853.90000000 WQLV227 A North Las Vegas CLARK YE
Southern Nevada Area Communications Council 853.90000000 WQLV227 A CLARK YE
New Freq
no one updated the database I guess