Whether you take McMurray or Fuller past the quarry (preferred imo), the primary issue is crossing Tinemaha Creek
here. Unless it's been graded recently, which is highly doubtful (call Inyo County and see if they have any info), the boulders will bring you to a full stop in anything other than high-clearance. Worst case, park there and hike the extra 2.7 miles to the TH.
Also note, that the FS abandoned the trail years ago and nature has been hard at work reclaiming what's hers. Expect some head scratching and hand-wringing if you haven't been up there before---and know which way you're supposed to go from the start or you'll spend a day swimming in willows...