You'll love Huachuca. I went there in '93 for 97B school. Went back there again in '95 on training mission. Make sure you get to Tombstone plenty, I suggest TD's club in Tucson for naked women. Be sure to get a lap dance, it's worth the 5 bucks. (was passin through in '96 and found that out)
The mountains are awesome to hike in, but take a friend or at least tell someone when and where you'll be going and returning. Take some time to drive through the canyons, they are great. Mexico is ok, touristy thing to do I guess. Sierra Vista is what it is, a military town. Plenty of places to eat, that's for sure. If you get to Bisbee, be wary of the locals cause they sure are wary of army types. THey feel the army is spying on them all the time, we just conducted trainng exercises there.
There was a great pub on post about 100 yds from the student barracks, cheap beer and plenty of pool tables. The rec facility was nice too, big indoor pool there with diving boards.
Earlier post was right about non-camobat arms, I started as Infantry and branched over, what a difference. Give yourself plenty of time to get acclimated to high altitude.
All in all, I really enjoyed my stay there, you should too.