I would take a drive down through Big Sur and head east at Paso Robles back to Yosemite. On the return trip you could head up the Mother Lode on Hwy 49 and go see lake Tahoe. If no snow, you could boondoock overlooking the Rubicon Wilderness basin west of Hwy 89
Make reservations NOW for Plaskett Creek or Kirk Creek and Cambria in Big Sur. Stop at Hearst castle if you like that sort of thing. Oggle the elephant seal colonies on the coast north of Cambria.
Don't forget you WILL need to bring tire chains for one axle of your tow vehicle, and one axle of the trailer - NPS will NOT let you in park that late in season without them, and there is no access to Yosemite Valley with a rig your size without going over a pass subject to snow. They get really bent out of shape if it snows and they need to escort you out of the park!
Best of all - have fun.