To get to Dirty Shirt, drive past South Park Rd. (the road you turn on to get to Desert Tortoise). After you loop around on that road and start heading towards the lake again you’ll see a road on the left. That goes to Dirty Shirt. It’s easy to miss because you almost have to u turn to get to it. If you make it all the way to the Ranger Station, just turn around and look for it on the way back. On weekends you’ll see a lot of activity there too.