The worst part of the road is along the floor of Saline Valley. The washboards will kill just about anything short of $200 a piece shocks, and rattle half the bolts in your vehicle loose. I have not seen worse washboards anywhere in the park. It's about 20 miles long for this section of the road.
A few years ago, I went halfway out to Saline with a friend. He was driving. I kept telling him to slow down, as he was going about 20 mph. By the time we got to the Salt Tram, the shocks were blown on all four corners. OF course, then he let me drive!
Unless your Wrangle is built, take it far slower than you think you should. My XJ is very well built, and I'd still take it slow on Saline Valley Rd. If they've recently graded it, you'll face a huge amount of sharp rocks., waiting to eat a tire. If they haven't, the washboards are hungry for more shocks.
Yes, all sorts of people have taken all sorts of vehicles to the springs. I get that. Myself, I error on the side of caution, because I really don't want to give Miller's $1500 or more to tow me out.
Conditions change significantly through the year. Once the snow hit, South Pass may become impassible, mostly because Grapevine Canyon is on the north side of the mountain, and the ice becomes treacherous. If a storm comes through, the valley floor is susceptible to significant washouts. Not trying to discourage you, but rather make you aware of the risk potential.
David Bricker / SYR