Many will say this is the place to go to camp/hike, and it's admittedly
very busy, and "commercial" (as I remember the Valley), but it's still awesome:
Yosemite.
The view you get when entering the park from the South entrance (the busiest) is just unparallelled, and something that stays with you permanently. Good luck finding a camping spot in/near the hiking-access-/supply-/souvenir-friendly Valley, though.
If you want something on the easy- to medium-difficulty-level in terms of hiking, you can take the John Muir Trail from Happy Isles (Vernal Falls, Nevada Falls, and beyond ifya dare! :Q ). Something a bit harder, but truly rewarding, and soul-invigorating are hikes to Glacier Point (where you can step right up to the very edge of sanity, and look down upon creation), or Half-Dome (
BIG-TIME ditto!

). I've also heard that entering the park from the North (entrance/roads closed in winter, for good reason!) can net you some amazing panaromas of the Sierras.
I know of places-to-go, and hot spots in SoCal, but not NoCal.

Can't help ya there....
Enjoy your stay in Cali, where we have yet to erupt in total social breakdown, suffer a huge economic collapse, endure months-on-end of rolling black-outs, OR fall into the great Pacific Ocean.

Sorry "Doom"-sayers.
