Roadside attractions like this are common out West, especially in the desert. People will stop and look at literally anything so long as it doesn't belong there to begin with.
I used to do my Navy training at Yorktown -Cheatam Annex, right down the road from that park on Rt 199. Always passed by it, but never checked out the park.
I saw in one of the first pictures, the front section of what appears to be the Presidential 737 Jet? Any clues as to what happened with this after the park closed?