In that case, head up to the mountains and the NF campgrounds. Dry camping. Weather in summer is warm during the day and cool at night. Almost always a body of water (reservoir, river, etc.) at or near the campground. Lots of trees and shade.
I'm in Northern California, so my favorites may be farther away than you'd prefer, but here are a couple of my favorite areas:
Lakes Basin area - Plumas and Tahoe NFs; lots of campgrounds to choose from, some on creeks/streams, some on lakes.
Ice House, Union Valley Reservoirs and Loon Lake - El Dorado NF; lots of campgrounds that vary in clientele. Ice House Reservoir campgrounds cater to water skiers, jet skiers, etc.; Union Valley campgrounds are more family oriented with some boats; Loon Lake is more remote/secluded.
1975 American Clipper RV with Dodge 360 (photo in profile)
1998 American Clipper Fold n Roll Folding Trailer
Both born in Morgan Hill, CA to Irv Perch (Daddy of the Aristocrat trailers)