You will be crossing these districts 4 and 12 from Las Cruces to AZ and can possibly here district 8 from Las Cruces to El Paso depending on several things.
Pertaining to I-10 From AZ going to TX, (remember its a duplex so youll need the TX/RX freqs to hear both sides)
Deming D12 from AZ line to Lordsburg, Deming to West Dona Ana county (Las Cruces)
155.565 dispatch
155.655 mobile
Las Cruces D4 From Deming (Luna county half ways) to LC to Sunland Park and TX state line
155.520 dispatch
155.535 mobile
Alamogordo D8 This may be heard along South I-10/I-25 to El Paso if a D8 unit is near the "gap" basically his repeater is carrying across the gap youll see the mountains end for a distance then build back up with a gap that goes towards chaparral NM and his signals going through the gap would be to your east going south on I10/I25. If a SP is on the top of the Saint Augustine pass east of Las Cruces it may carry over also as the highway 70 goes right through this and where Districts 8 and 4 meet along the mountains going south east of Las Cruces.
155.790 dispatch
155.730 mobile
VRS, this system is setup different ways depending on each time frame and version or type of radio each unit/officer has. The whole NMSP setup is kind of funny and old but it works but too much to go into detail lol. But monitor the VRS portables relay. It works near units and carries the signal pretty far from the unit repeater. Some officers leave the VRS on when there home sometimes for short periods and many do live along Interstate 10 in communities going south. Youll hear all traffic in his scan list on the VHF side thats relayed to the VRS UHF. However you may pick up a mexico chatter being close to the border on this channel, some areas of NM there is DPLs used but I dont not recall them. But some officers carry 2ch Ht1000s or 16 Channel Ht1000s UHF radios and the 16 channel portables has the local UHF med channel to monitor.
NMSP VRS for portables 460.150
Monitor these as depending on every group of officers or pair some like to utilize these with the other or group on duty. 155.550 is usually used if the duplex goes down or fails on either side of someones repeater and mostly for car to car talk.
155.550 state car/ NMSP T/A
155.475 LEN
154.920 NMSP F4
155.370 NMSP LEN
155.160 NMSP E Net
155.4825 VLAW32
South west intercity base to base
154.800 Output
154.875 Input
I would also monitor the sheriff freqs from Hidalgo county, Grant County, Luna county, and Dona Ana county. Sometimes NMSP may be utilizing this if hes alone and the officer works close with a deputy friend on the highway along I-10. Dona Ana sheriff youll want to enter all the output freqs listed in the RR database page as they do use different repeaters for north and south. Youll hear sunland park NM if you enter that too.
If your going into El Paso look at the El Paso county TX page. Youll hear the sheriffs office and surrounding VHF towns police depts like Anthony, Horizon, etc. Youll hear Sunland Park all way to down the Mesa and I-10 and NMSP/Dona Ana SO to Sunland Blvd / I-10. Utep still uses there conventional setup but has a 2nd mobile radio thats on the El Paso trunking system.
Texas DPS (p25 clear) in El Paso can be heard all the way into Dona Ana and Otero County. Troopers will cross into New Mexico by chaparral in Otero going into Dona Ana in these two counties using the highway that goes off from 54 south near Fort Bliss range that crosses the "gap" back to I-10 into West El Paso. This gap highway saves allot of time for various law enforcement wanting to get on the other side of the trans mountains. El Paso sheriff also uses this route and can be heard into Otero and Dona Ana (Las Cuces). There are various deputies and cops from both states living on either side of both state lines since that area is jammed with towns on both sides. So you may see NMSP in El Paso west, or Sunland NM cops in El Paso since they live there or El Paso deputies living in Sunland Park.