Update to the directions: Once on the road marked "Sand tank 4 miles" You'll actually follow the signs for Forest Road 677, not 667. Also you'll make the first right about a mile down the road, if you keep following the most used route you'll end up at a radio tower as I did.
You'll probably want your 4-wheel drive after the first gate now, the road has probably deteriorated some since the directions were written. It's mostly decomposed granite though, so you wont have to worry about rocks gouging your underside. I made it in a stock 08 Jeep Wrangler with the S package. That means 31 inch Goodyear SR-A tires and 4-lo. I didn't have any problems or feel nervous at any time. I wouldn't take a full size pickup or anything without 4-wheel and decent clearance down there though.
As for the hike I didn't find the path hard to follow until getting up to the ridge. Just follow the cairns. There's a couple spots where there are multiple paths and cairns to follow, but they all eventually come back together. You can tell a lot of work was put into making the trail, it's too bad the forest service has quit maintaining all the trails in the range.
Once on the ridge to gain the true summit of Cottonwood is an exercise in frustration. There is a path in spots but it also disappears quite often, being overgrown with manzanitas. If you're wearing shorts be prepared to have your legs be torn up. The summit doesn't appear to see much use, the last summit register entry was from February 15th. It looks like several NOLS and SAHC groups used to go up there, but they haven't been signing it for the last couple of years.
There are some pretty amazing views up here of an oft ignored area. The range is between the much larger Pinalenos and the Galiuros with their much more famous history. I didn't see another person from the time I got onto Klondyke road until getting back to highway 70.
I did see a lot of wildlife up here. 3 rattle snakes, another tan colored snake I couldn't identify, 1 buck and 3 does, along with several scorpions and rabbits.
After visiting the Santa Teresas I definitely want to check out Holdout Canyon and Blackrock, so if anybody has any info could you please let me know? We could even plan a trip. I will not be coming back out in the summer though, it was hot!
||Wildflowers Observation Isolated