I haven't been to Sand Flats, but Shafer Trail is easily done in rental 4x4s (Tahoe/Yukon, Suburban/Yukon XL, new Explorers, Armadas, and even Acadias). We take a trip there a few times a year for work (oil&gas) to show new employees what they are looking at in log data in real life, and we rent SUVs (those listed…