20 miles north of Ketchum Route 75 opens up into a beautiful, wide valley. The road follows the west side, the Big Wood River is on the east side, and along here there is a big, flat open area in between, with good-ish gravel roads over to the edge of the river where many dispersed campsites are set up. Pretty cool! This is the same river that flows through Ketchum and Sun Valley.
A great little find on US 20 east of Craters of the Moon. Just a nice field with picnic tables and a a few trees on the edges. No services of any kind that I can see - "pack it in pack it out". They're just giving the fishermen a nice place to park their campers. Pretty sweet! Update! There IS a pit toilet, and there is a water spigot! But no place to dump trash, which is fine with me. And there is a donation box.
I came here 15 years ago with abalone-diving City friends. I'm not even sure that's a thing any more. Anyway, the campground is still here and it's still awesome. They have spots available when no one else does, and it's the simplest check-in ever: Pay them ($5 off for cash!), they give you a receipt for your windshield and tell you to park at any picnic table/fire ring that's not occupied. The rest of the world seems to get more complicated and bureaucratic, but this is the easiest damn check-in I've ever experienced. Checkout 2pm. Ocean Cove Bar and Grille is a sweaty uphill 3/4 mile walk away. Basic bar food, but great view of the ocean and campground.
Somewhere between Natural Bridges NP and Lake {Powell (Hite UT) there is a sign to turn off for a Historical Marker. On that turnoff there is at least one really quite nice place to camp. There was already a fire ring, so I know it's OK! A couple of miles south of the Jacobs Chair sign.