Year, and years ago.....when selling DS's car we were having trouble selling it or even finding anyone interested.
Then I decided that we needed to "list" it in a bigger market. We lived in a pretty good size city so we changed and listed in the next larger city (25 minutes away). We had tons of calls coming in daily.
So I would check around and list it in as many areas as you can and in as many places.....check out the social services want ads bulletin board, local thrift paper, car papers, newspapers, craigslist, local used car dealers.
Is it possible to park it for the weekend in a visible area with a for sale sign in it? That is what many people do around here. Older vans in fair condition usually get sold for cash from the large growing Hispancic population.
Good luck and keep us posted.