You've got 4wd, boondock at Lone Rock. Then anchor/tie the boat a few feet off the sand right in front of your camp.
Last I remember, Stateline ramp came out of the water before the Wahweap ramp did. But I haven't been down there lately... You could also stick it in the water at Lone Rock. I launched/retrieved a 19' runabout Lone Rock in a 2wd dually years back.
The farther north on the beach, the harder the ground is. As you go south the ground gets more sandy and 4wd is a must. Being June, you might expect to have to run down the beach a little ways. Don't forget to air down if you need to!