Check out Idyllwild. It is in the San Jacinto Mountains about two hours east of Los Angeles on the way to Palm Springs. Actually the Palm Springs Airway goes up to a park on this mountain range. It has a Lake though officially not for swimming in, it is wonderful to walk around it. There are lots of hiking trails form easy to serious, there is a charming town with lots of local artists. There is a paint your own pottery place and nice craftsy stores in town, a very sweet one-movie movie theater that also serves as the local video rental store, and delicious restaurants, some with musical entertainment. A lot of folks rent out their cabins so you can cook meals, pack picnics and eat out for dinner, hang out, play games, go for walks, do nature crafts. The Nature Center is a wonderful day, there is a small museum display about what grows and lives in the area, they have kids activities that are engaging and educational, and there are several different hikes of different skill levels. Idyllwild is one of the blessed places in the world and not too touristy that you feel overrun with other visitors and there are no (or very, very few) chain stores, all locally owned.
We have spent lots of time there so if you choose Idyllwild as your destination you can send me a personal message and I'd be glad to make suggestions on how to fill-up your time there.
http://www.idyllwild.com/
A nice Inn where we've stayed http://www.thelodgeatpinecove.com/
I'm jealous of anyone just dreaming about going to Idyllwild. It has a very restorative quality about it and we all love it when we can get there.
Have a great trip with quality together time.
P.S. For another trip I would check out is Julian near San Diego. Also charming and known for their Apples, Apple Pie, Cider, etc.