The road into Saline Valley from South Pass is 2wd high clearance, unless a recent flash flood tears it up, in which case it can be anything from 4wd to impassible. The road is the world's worst possible washboard. Go over it at any speed, and expect parts to fall off.
The road through North Pass is less washboard, a bit shorter, but is a longer way to get to from the south.
The road through Steele Pass is 4wd, short wheelbase preferred.
Since all of this is in the National Park, there is no driving off established roads. There are a couple of side canyons in Saline Valley; perhaps the most interesting would be to take Lippencott Rd. up to the Racetrack. Lippencott has a very bad reputation. It is 4wd, low range required, and the shelf road is very narrow in some spots.
With a 4 day weekend, you could come in via Lippencott Rd, camping near the Racetrack (no camping at the Racetrack), so you could see the rocks in the late afternoon. Then head into saline the next day, staying 2 nights at the springs. Then go out Steele Pass or South Pass, depending on time.
David Bricker / SYR