When Lake Pleasant lake water is low, from PHX travel north on I 17 and exit west on Table Mesa Rd. Follow it down to the park road closure and from here one must hike into the Agua Fria River downstream past Bolder Creek and exit the river on the north west side on Old Table Mesa RD. Follow Table Mesa Rd uphill for about a mile and a half until you top out at the saddle. Here turn south and climb a trail to Indian Mesa. Sometimes trailhead rock markers mark this location. Another 1/2 mile to go.
During the winter when Lake Pleasant waters are high and the Agua Fria River is flooded travel behind Lake Pleasant on Cow Creek Rd. Follow Cow Creek road past the old Castle Hot Spring landing strip (now where ATV riders stage for the Crown King ride) and turn right on the road that leads to Humbug Creek (signed). Follow this road all the way past Humbug Creek to the previously mentioned saddle.
Here again follow the trail uphill. There is only one way into this well protected fort and it is accessed on the south west side of the mesa.
I hope I helped and let us know how about your adventuer
Old Table Mesa traveling up toward the saddle trailhead.