This is an incredibly remote, rugged, and challenging range highpoint on the Barry M. Goldwater Range. It's also one of 73 summits in Arizona with over 2,000' of prominence; in fact, it's the lowest peak on this list, but that assuredly does not make it the easiest! Though getting to the top is difficult, the experience is rewarding, and you will get to see a part of the state that very few individuals ever will.
The Mohawk Mountains, like much of this part of the state south of I-8, is on the Barry M. Goldwater Range. A permit is required to access the BMGR/Cabeza Prieta complex, but it is free and easy to obtain. This is a bombing range--your hike will be punctuated by the occasional distant sonic boom--but the range is not in an active bombing area. Even so, on the off chance you should encounter any unexploded ordnance, don't touch it.
This area is incredibly remote, and if you should become seriously injured, you're pretty much on your own. Do not attempt this "hike" unless you have abundant experience with rugged, off-trail routes. Do not come here alone, and leave detailed plans of your trip with friends/family. Bring plenty of water, and know how to get your vehicle out of a tight spot. Definitely do not come here in summer!
Lastly, this corner of Arizona is well-known for illegal border crossers. It would be unwise to leave a vehicle in plain sight on a road (though you should be okay at this trailhead), or leave valuables in your vehicle. You'll probably encounter border patrol at some point--just show them your permits and you should be fine.
From where you parked, aim for the initially wide and prominent drainage basin leading almost directly toward the summit. Your aim is a 2250' saddle. You may choose to either stay in the bottom of a wash (which eventually leads through a rather neat small canyon, or to stay left and make the easy traverse above the wash for a ways. Either will work. Eventually, the wash and traverse routes rejoin, and you can simply rock-hop your way up the drainage as you moderately gain elevation. Aside from bits of brush here and there, this part is easy.
Ahead of you, there is a large reddish-black tongue of rock that appears to be blocking the way. However, it can be circumvented on the left by going through a patch of slightly heavier brush. Beyond this is perhaps the crux of the route: at around 1550', the drainage splits. Do NOT attempt the branch on climber's left--it initially looks easier, and can be ascended a ways, but you'll ultimately find yourself cliffed out. Instead, examine the gully system on climber's right. There is a 30' tall waterfall, nearly vertical, and with probable good handholds. However, it's 4th/low 5th class, and unless you're very comfortable with such terrain or have ropes, I don't suggest you try it. Instead, ascend the nasty, class 2/3, steep scree slopes to the right of this waterfall for perhaps 250'. This is a nasty bit, with plenty of brush and stabby plants and untrustworthy rocks. Don't trust your handholds here! Continuing uphill you'll eventually get "squeezed" into a spot with a rock slab on your right and no real way to continue upward. Here, double back and descend 50' or so back into the drainage, which is again easily passable for a ways. Remember where you rejoined the drainage here, because on the way down you'll need to leave again at this spot. If you keep descending the drainage past here, you'll find yourself atop that 30' waterfall!
From here, ascend the remaining 400-500' to the obvious saddle, really more of a notch in the ridge. Near the top it steepens again, but not as badly as before. Catch your breath, and enjoy the view! You're at the edge of another drainage bowl, this one pretty tame by Mohawk Range standards. Saddle 2590' is pretty much straight ahead and is the last fairly gentle notch in the ridge; to the right of that saddle is the rocky summit. Now aim for saddle 2590' by means of traversing and/or descending the drainage bowl, and ascend the opposite drainage to the 2590' saddle. This part is relatively easy and you should be able to figure it out. At this second saddle, spectacular views open up to the east. You're now only a tenth of a mile and 200' below the top--but now it gets tricky again!
The final ridge is very rocky, knife-edged, and (at least when I was there) ferociously windy. And the closer to the summit you get, the more the slopes to climber's left turn into sheer cliffs. Be careful here. Staying directly on the ridge crest would probably be borderline technical climbing in spots, but the good news is that you can usually bypass it on climber's right on class 2 rocks and slopes. So finally, you're at the summit block, which is almost entirely ringed by impenetrable cliffs at this point. There's only one way up, and it's a doozy. Okay, it's not that bad--class 1/2 at worst--but if you fall, you die. There is a flat, even ledge that's about two feet wide, a dozen feet long. It has a bit of loose rock underfoot, and one palo verde tree growing out of the rock on your right (it's both a help and a hindrance). There's a sheer, several-hundred-foot dropoff to your left. Walk out to the tree, take a deep breath, and swing yourself to the other side. Or alternatively, clamber over the trunk of the tree for a slightly less exposed move. I did both. From here, (carefully) make your way up the last dozen feet and top out! Admire the stunning views of this most remote part of Arizona. Sign the register, if there is one; I didn't have time to look, unfortunately.
When you're ready, return the way you came. The crux back in the first drainage requires care, and in my case, lots of slow scooting down on my butt. Don't wear pants you care about!
Unless there has been a recent rain, don't count on any. This is one of the hottest, driest parts of Arizona.
Camping is allowed in the BMGR. There are a multitude of good spots to camp near the parking area, though none are likely to have water.
WARNING! Hiking and outdoor related sports can be dangerous. Be responsible and prepare for the trip. Study the area you are entering and plan accordingly. Dress for the current and unexpected weather changes. Take plenty of water. Never go alone. Make an itinerary with your plan(s), route(s), destination(s) and expected return time. Give your itinerary to trusted family and/or friends.