You're exposure to Salvation Mountain may be a direct result of the Slab City Riot(s), or you may have had hippie-ish' family members or friends who took you out there? Come to think of it, I just posted up some old Riot pictures on the 9th... ironic? prophetic? Don't know. Either way, for those of you who have been there (and even those thinking about going) it's noteworthy that Leonard Knight past away Monday (Feb. 10th 2014) at the age of 82.
My first trip there was during the 2009 Slab City Riot (thank you Biltwell for the introduction). The "Slabs" are a mere quarter mile (or less)(as if there's property lines or something?) from Salvation Mountain. To even get to the Slabs, you have to pass Salvation Mountain, so if you've been to one (the odds are good) you've been to both.
I've been back probably nearly a dozen times for one reason or another (pre-runs, family vacations, weekend jaunts) and each time seen something (if nothing else) interesting.
There's google news articles galore about Leonard if you're interested, but merely know he's now left this world deserves a thought toward his eccentric and artist life.