Agua Caliente/Milagrosa Canyons can be accessed from taking Tanque Verde Rd east to Catalina Hwy. Turn Rt on Synder Rd, then left on N Avenida de Suzenu. Park at the end (you'll probably see a bunch of cars - this place is full of Mtn Bikers as well as hikers). You hike through a posh neighborhood down a mostly paved road to get to the actual trail.
I got directions off the web, which turned out to be a mistake. When we returned home, I checked out the internet for a better description of this hike and was able to find one detailed one, with pictures (by Sirena), showing a group doing this same loop in reverse. It involved climbing steep rocks straight up from the canyon floor and appeared to be the kind of hike you should do with a guide and/or group.
After hiking down the road, you turn left not far after the intersection with Whetstone Rd, after passing through a wash...then veer left up a crushed, white rock/dirt that climbs slowly up a ridge for a quarter mile, then becomes quite steep for about another half mile or more According to our directions, after then descending from this ridge into the wash (Agua Caliente Wash), where there is a large, flat rock shelf. That is true - we saw the rock shelf and stopped to take a break there. You continue up a hill, turn right at a Y, then begin descending into the wash (presumably the Milagrosa wash) then up the other side of the canyon and back in the direction you came...meeting up with the original trail near the very end, within a mile or so of your car.
The directions didn't include any distances, or an overview, but I had the general idea because I've been to Agua Caliente Wash twice, although many years ago. The first half of the loop I've done, but many years prior. I've twice hiked in via the trail described above, until reaching the wash (about 2 miles, maybe a bit more, from the car), then turned around.
In this case, we got off track right at the beginning, partly because the description of where to turn left (shortly after leaving the paved road, which was only about a half mile's distance) was not great ...I can't blame the directions fully, though, because I've been here and remember making the same mistake on a prior trip. It was only after we'd gone too far, crossed Agua Caliente wash, and began up the other side that the trail description made no sense. We turned around to look back from where we'd come and right then we spotted a couple on the other side of Agua Caliente wash heading up a ridge, and we both realized THAT's the ridge we should be climbing up. So we turned around and more or less followed them.
From here we hiked up, at some points quite steeply, across bleached out rock. It was obvious why mountain bikers love the trail, as much of it is similar to Utah slickrock. You couldn't lose the trail because deep canyons dropped off on either side. Also there was a gate, just as described in the directions. Then you began to descend into Agua Caliente Wash.
Our next wrong turn was after we'd reached the bottom of the descent. After leaving this down point (we'd hiked about 2 miles total so far) in the Agua Caliente wash, next to the large, flat rock shelf, the directions described climbing up the hill and coming to a Y. But there was no mileage estimate from the wash up to the Y. About a 1/2 mile out of the wash, we did indeed come to a Y, but the right turn was covered with dead century plant stalks, which someone had obviously placed there. We took this right turn anyway, thinking the trail would soon begin descending into the canyon. But the trail petered out into rock and there was no obvious way to descend into the canyon - it was just a sheer drop off into a wash very far below.
Having now checked the internet and looked at photos of this loop from the other direction, I'm relieved we didn't try to do the loop. Climbing down into the canyon would not have required rope but it certainly would require knowing where you were going as the trail is simply the rock sides of the canyon! Indeed, it seems best to do the loop from the other direction, as it would be easier to climb up steep rocks than down them. Peering down into this canyon from the ridge almost creates an optical illusion, making it difficult to tell even how far down it is...in other words, it drops precipitously and is not inviting for a climb-down.
Nonetheless, after realizing the Y we'd taken wasn't going anywhere (I still do not know if this was the right way - it's quite possible there was some point at which we should have begun climbing down nearly vertical rock after the trail petered out), we backtracked onto the main trail and continued forward, and up...thinking we would come to a more obvious Y and/or a way to descend into the canyon. This trail climbed steadily, but not unpleasantly, along a ridge. The views of both canyons on either side of us were fantastic. I stepped just next to the edge a couple of times to get the full affect (Tim declined - he gets vertigo from heights). We walked up and covered about another mile...soon realizing that getting down into the canyon from where we were would require 1,000 of rope and rappel devices...thus sparking another conversation beginning with, "this CAN'T be right." Part of reason we had gone so far up the ridge is that we ran into 3 other hikers about halfway up and told them we were trying to do the loop, and they said, "oh it's up ahead," but I now question that information as they had not themselves done it.
I felt determined to find the Y this guy had been talking about in his AZ Hike directions, so we could begin descending into the canyon, through the wash a 100 feet or so, and up the other side. But we agreed that directions just weren't going to work. We'd gone about halfway, although hiked quite a bit further due to turn-arounds, and figured heading back the way we came was the best choice.
We estimated we hiked between 6 ad 7 miles, probably closer to 7 as we were out almost 3 hours. I did love the ridge hike and we got a great workout. The other upside to this failed journey is that there appears to be a thru-hike (shuttle) from Molina Basin to where we began this hike. It's a popular mountain biking trail, because it's down-down-down. And that seems like it would be a blast to hike, with shuttle.
I also found this hike mentioned on a Green Valley Hiker's Club list and it was rated B, Difficult. Now that I've seen the photos of all the rock scrambling (not to mention route finding) I think I understand why.