On your way up Highway 140 to Yosemite NP or traveling along California's historic Gold Rush Highway through California's Mother Load Country (highway 49) ... One might stop and spend a day in historic Mariposa Ca.
It has a Town Museum with lots of mining history, quite a lot of historical buildings and shops and restaurant...
Here is a few links...
http://mariposamuseum.com/
http://www.homeofyosemite.com/
There is also camping (with power and water) at local fairgrounds a few miles south of town on Highway 49 south.
Dale