Suggestion Oregon, Northern Calif for this summer

Lake Billy Chinook area and Crooked River Ranch RV park overlooking the Deschutes River.

Don't miss the Astoria in Oregon.

Thanks all. LOL the one and only encounter I ever had with a rattlesnake was at John Day Fossil Beds and ever since I get a sick feeling in my stomach thinking about it. Thanks for the warning. I might have to rethink this.

Oregon designates some of their state parks as first come, first serve. That said, even those fill up in the summer. Arriving at check out time on a Sunday or Monday can get you a spot most of the time.
https://oregonstateparks.org/index.cfm?do=reserve.dsp_firstcome

Gets pretty hot at Cottonwood during the summer. Watch for rattlesnakes. Nice new facilities though. Its a favorite of some of my friends here in the Bend area. Drove out there a couple weeks ago but the river was flooding and covered the road with about 3 feet of water.

Haven't been there yet camping, but have driven on 206 through the approx area. I'm sure that certain times of the summer will be "warm"!! Hilly, dry, sagebrush and grass, picturesque!! Not very high altitude, aboot 600ft. Not sure how windy it can get, but if it's like here in the Dry Shi**ys, it can be a bit at times!!!!

We tend to stay in the forests at higher altitudes esp in summer. Have thought about going to Cottonwood in early spring or later in fall.

Tacquala, have you ever been to Cottonwood Canyon State Park I wonder how that is in summer

Can't recommend any N CA areas, but many SE and Central Oregon spots.

Steens Mountain, Three Creek Lake/Black Pine Springs area near Sisters, Cascade Lakes (Century Drive) area near Bend, Paulina Lake/Newberry Crater sites, John Day Fossil Beds/Painted Hills, Magone Lake, lots of NF dry sites along the John Day River various forks, Sumpter gold dredge areas!!!

Coast or mountains?

Orick/Crescent City/redwoods area in Northern CA might have availability. You can hangout on the beach, hike in the redwoods, and see Roosevelt elk. Fewer people than say San Fran, but it is California after all. Trinity Alps would be nice mid July or later since the snowpack is so high this year. Lots of hiking.