Driving up Whitney Portal Rd from 395, prior to the left turn for Tuttle Creek Campground, you will see on the right hand side dirt roads leading off into some spectacular huge boulders and canyons. There is dispersed camping there.
This is area is to a great deal BLM land. It would be good to check with the local BLM office. BLM rules for ATVs or OHVs, are typically, that they my be used on roads only. In other words, no cutting across areas with vegetation...so in the true sense of the word ‘off road’ ... no.
Enjoy the ride but show respect. Leave it as beautiful as you found it. It’s that beauty that drew us there.