If you like plays/Shakespeare Ashland Oregon is super awesome, probably my favorite place to visit in the summer.
San Francisco is definitely cool though, live near there and I love it! Great city. I could give you some tips of places to visit in SF if you wanted.
I also really like going to Disneyland haha and Laguna Beach is super cool place if you haven't been. Very laid back lots of surfing and art galleries.
San Diego is pretty cool too, La Jolla area is super pretty. More beachy vacation than city.
Seattle is another option? Never been but I have a lot of friends who live there or have visited and say it's really wonderful.
If you like more outdoorsy things I would recommend Sedona, Arizona, lots of hiking trails, beautiful rock formations, all the dirt there is this bright red color. It's a great little town. More dry desert feel.
Sounds like fun