You can drive out to the salt flats, weather permiting. There is a paved road:
BLM;
A better article.This is pretty much the middle of no-where Utah. The northwest corner is empty, probably because of the salt flats which cover a large area. I was sent an advert for some amazingly cheap land, the advert was reticent about just where this land was but some sleuthing determined it was just above the BLM land containing the salt flats and that land wasn't much better than Bonneville. Also most of the land, especially to the south, is a military reservation where the Army, long ago, did open air nerve gas testing.
I'd check Wendover for a camground.
You are talking about a full day diversion from your trip south to the Four Corners Parks and there is darned little to see except some blindingly bright white playas.