I'd just have hatch chiles delivered by UPS instead of going yourself. Waste of time.
This.
My comment about Canutillo was tongue-in-cheek, and you'll find Hatch chilies where ever you find them.
If you do go to the area, go into El Paso and try Kiki's Mexican restaurant. It's been a favorite for 50 years or more. Go down I-10 another 35 miles or so to Fabens and take that exit headed north for about six or eight miles, and you'll encounter some of the best steak dinners you'll find west of the Pecos (Cattleman's Steakhouse). Just south of Las Cruces is a place they call "Old Mesilla," and there you'll find the La Posta Mexican restaurant which has also been a regional favorite for about 50 years. My uncle and I had lunch in there one day with Bob Lilly sitting at the next table. Excellent food. And I'm sure a little research will turn up other treasures in the area. I haven't lived there since 1994 or so, but some stuff is still the same as it was.