If you like to drive, a good day trip from Groveland is to take Tioga Pass and go all the way to 395. Then come back over 108 (Sonora Pass) all the way back down to 49 and then back over to Groveland. Leave early because it is a long drive, but it's doable in a day. There's quite a few different things to see and do along that route.
You'll need to check the status of the forest roads where you're staying if you like getting into the back Country. The RV park you'll be at was surrounded by the Rim fire last year so all the area around you will have been burned. I know there are some areas still closed up there but I'm not sure what has been opened back up. Cherry Lake is a nice ride but that road will go right through the heart of the burned area. It's all nice and green again, but most of the trees are dead. Did open up the view though.