The Evergreen Lodge is right on the doorstep of Yosemite National Park. A day trip to the valley floor is about an hour away (without traffic). It is possible that next summer you would need a reservation to access the park, so please check the NPS website for more info about booking a spot!
This is San Francisco's Family Camp. We have been here as a family numerous times. It is less than a mile down the road from Evergreen Lodge. Easy walk or bike ride. You can purchase a day pass to use their pool, swim lagoon and beach, etc. Fun day trip if you are bringing the kids.