I would suggest you just hike or bike up Garden Canyon as it is a moderate hike. You can get a pass to get access to Fort Huachuca to see the museums and Garden Canyon. The passes to base are available at visitor control at the Van Deman Gate. The Road to Garden Canyon is now washed out. You must walk up now to see the canyon. Not sure when that will get fixed.
Garden canyon was Named Hayes & Tanner Canyon in the 1800s when it was used as a vegetable garden to supply the troops. The museum on the fort showcase the Buffalo Soldiers, African-American men and women who served in the Army from just after the Civil War through World War II. Including the time, they chase after Poncho Villa into Mexico with General Pershing.
There is a lot of wildlife in historic Fort Huachuca. Around the museums and old parade grounds there are huge Mexican Turkeys, Deer and Javelinas. Garden Canyon has water flowing through the slot canyon ,which makes for some great bird watching. There are old Indian petroglyphs up Garden Canyon too. To read more about the petroglyphs go to the link below.
In the spring there are my yellow columbine flowers blooming next to the creek that runs through the upper canyon. There are many sphinx months feasting on the fall flowers too. I call them hummingbird months, because that is what they look like. They started out as horned worms on your tomato plants and then they become quite beautiful as the sphinx moth. The road starts by the firing ranges on fort Huachuca which goes through some very nice grasslands where it is not uncommon to see Sonoran Antelope and deer. The road is paved for 6.7 miles and then turns into a dirt road then the road ends as the canyon boxes out. The Garden Canyon Road ends and becomes a rough 4-wheel road up to old gate seven. Gate Seven has been blocked to prevent access into the Army Fort. In time gone by the road used to go over the Huachuca range. There are many firebreak roads on the way to gate 7, which makes for some great Mountain Biking. There are two hiking trails, one at the bottom of the canyon and one at the top. Scheelite trail is 3.6 miles a challenging hike and goes all the way to the crest trail which is the top. The trail at the top of Garden Canyon is Saw Mill Canyon trail is a 2.2 miles moderate hike to the Top to the crest trail. You can use the two trails together and make a loop. When you are hiking in Huachuca’s there are no easy hikes. Once you get to the end of the canyon it is straight up to the top on most hiking trails. This is an easy day trip from Sierra Vista with many outdoor activities in store. There is a rappelling area next to the petroglyphs for all the climbers out there. It is a must see for visitors and locals alike.
