This week is pretty hot. I'd be inclined to stay near the coast. I've never been but I understand you can camp by your plane at Oceano. Used to be able to rent ATV's to ride the sand, but I think that is over. Still might be nice to walk along the ocean.
Flying the coastline is beautiful: Big Sur, etc. The San Fran Bay Tour (Golden Gate Bridge, Alcatraz, etc.) is described in another current thread. Then north over Point Reyes. Much of the coast route has steep terrain so no place to glide in the event of engine failure. I've done it in a BRS parachute equipped plane. Depends on your personal risk profile.
If you go inland and up into the Sierra Mountains, land at South Lake Tahoe airport, you can get a ride to the dock by Riva Grill restaurant and get parasail rides and I think they have that hydro wakeboard that lifts you off the water quite a ways. Stuff the boys should love. Plus flying around Tahoe, Emerald Bay, and Desolation Wilderness is pretty special.
Flying near Mt Shasta is stunning, but then you're used to big Cascade Volcanoes. If instead you follow the coast, Shelter Cove is pretty, but the lads may be bored. Nice hike to the black sand beach. Beware of getting fogged in.
Enjoy the time with them. Those were some of my favorite years with my boys.
Pierre