The location of the entrance gate is 106° 59' 2" W + 32° 59' 18" N. This should be good enough for your goto telescope.
From Las Cruces take I-25 to the Upham exit #32 and turn right. Continue 23 more miles. Halfway between mile marker 23 and 24 is the turn to the Spaceport which is another 2 to 3 miles to the east.
These pictures show the way. You can also use Google Maps.
This 5 minute video starts at I-25 at exit #9. Driving at 1200 m.p.h. You
end up at the Spaceport in 5 minutes.