I finally hiked up Martinez Canyon to the Jack Miller Cabin. A really nice hike for a cool and dry winter day - about 16 miles round trip with just 2100' elevation gain. No problems with access - the gate is unlocked at 68th and Van Buren. They are redeveloping one of the quarter-quarter sections of farmland between 66th and Van Buren and the gate; so you have to cross over on the farm roads at least once to get to the gate, but the farm roads are in good shape. I parked at the end of the road where the wilderness boundary sign is, but I think the wilderness might actually begin just a little past that point based on the maps. You do need a higher clearance vehicle to get to the end of the road and there are some sandy section; so if you don't have 4WD you won't want to slow down through those sections. I doubt I'd drive down the road without 4WD, but I'm a bit of a Nervous Nelly.
Some photos and my maps: https://kathywing.smugmug.com/Californi ... ck-Miller/
