From Tucson & Downtown Area:

Go north on Oracle to 1st Ave in Oro Valley. Go west (left) on 1st Ave. Continue over the CDO Wash bridge and past Lambert. Take an immediate right and follow the signs back into the desert.

From Phoenix:

I-10 east to the Tangerine exit. Go east on Tangerine to Oracle. Go south (right) on Oracle to 1st Ave. Take 1st Ave about 300ft past Lambert and turn right into the desert area and follow the signs.