First of all, let me just say that I love this site because of all the people who provide both information and support for members who love these old vans and want to keep them on the road. Some of us don't have tons of skills but it's nice to have those with knowledge, skills and experience who are willing to share and encourage us along the way.
I got out early today because we got some freezing rain in the Northeast today and the rearend of my box truck got a little squirrely after the first delivery. After hearing of a few multi-car pileups on the radio, I asked my boss if I could call it a day.
So, I put together a couple of word docs that show the 2 main sites I use to find listings. The rest I just find when I'm surfing the Inernet. If someone decides to do these listings, I'm available to help out with any questions. My instructions may not be the best because I've been doing it so long now, it's just second nature to me...
SearchTempest -
https://www.searchtempest.com
In the Keyword Field above, I typed in van(1961|1962|1963|1964|1965|1966|1967|1968|1969|1970)
For the other fields just choose all sales. Your zip code and any distance to get all US listings.
After you run it the first time, you can save the search and every time you open SearchTempest after that, the search is saved and you can just click on it so you don’t have to type it in again.
First time you run the search, you need to allow popups for this site in order for the results to show at the top of the page. When you hit the search button, it takes a while for all the results to come up because it searches Cragslist in over 700 cities across the US.
The other Search Engine I use is Facebook Marketplace (I know a lot of people hate Facebook, but they do have a lot of listings for Vintage Vans that aren't on Craigslist)
https://www.facebook.com/marketplace/category/vehicles


In order to narrow down results you have to use the filters on the left side of the screen. I usually put in the start year of 1961 and the max year of 1970. For Location, you can type in a city and state and the largest Radius allowed is 500 miles. Under Body Style, I choose Minivan. Otherwise you get way too many results to wade through. So you do a search , check the results, then choose the next city , etc…
I usually start with Portland, Or , then San Francisco, CA , then Albuquerque, NM, then Waco, TX, then Nashville, TN, then Tampa, FL, then Wheeling, WV, then Portland, ME, then Chicago, IL and finally Helena, MT.
Once you do it, you realize how much time it takes until you get used to it. For instance, I usually try to do it on the same day every week so when I start seeing listing dates older than a week, I just move on to the next result list.