Larry-
You defintely aren't the lone NSX owner in New Mexico. There are several of us in the Albuquerque/Santa Fe area. There's at least two of us who visit here on NSXPrime (I don't know the handle of my friend because I've never seen him post) We've got a great NSX Tech here in Albuquerque (Jack) at Montano Acura, and there are a ton of great places to drive your car if you're up for travelling. As a matter of fact, there are a lot of great roads just to the northwest of you near Silver City.
Be sure to get in contact with Spencer Smith if you are an NSXCA member. His info is on the NSXCA web site. We haven't had much for events here in a while, but I'm thinking that we will get some type of club event going in the next few months. Also, the RGRSCCA has autocross events every month or so here in Albuquerque which are a blast. There are usually at least two NSXs (mine and Spencer's) there and Spencer has a wealth of NSX knowledge to be gained.
Driving your car in NM climates isn't that bad at all. You don't have to worry about rain too much, but the late afternoon summer monsoons can really put a hurting on your car if it's left outdoors. Hail is almost always a threat when these storms roll through. I've noticed that on my black car, the fine sand that is in the air all of the time likes to stick to the exterior of the car. I haven't found anything that helps repel this fine silt from coating my car, so I've learned to live with it. That being said, I end up washing my car a lot more often than I would probably care to do.
As for washing your car, the water here in this state is VERY hard and has a lot of minerals in it. I would keep my car far away from any water sprinklers......my truck's paint is ruined because of the hard water spots all over it. They are REALLY bad, trust me. Also, when washing your car, it's extremely important to get it dry ASAP or you'll get those telltale water spots. I've run the gamut all the way up to using distilled water as a final rinse. Now, what I do is follow Lud's advice of just using a hose without any nozzle, and rinse the car off in "sheets" taking care not to spalsh or spray the water on to the car. This helps out a lot.
I don't know the e-mail address or the name of the NSX owner in Las Cruces, but I'm sure that there is someone here who can help you (or you can contact Spencer and he'll provide you with his info if he's an NSXCA member.)