I put this together based on some research tonight.  If anyone has corrections or additions, please let me know.

For years, though I couldn’t say how many, Marvin Long ran a Jeep Train that was also known as the Mule Train. As these photos show, he used at least two different types of jeeps to pull a series of two wheeled carts along the beaches of St. Simons, Island.  At least one source mentioned the train rides were for going out to the beach to collect shells.  Whether this was the principle reason or just one of the events is less sure.  Whatever it was they got to do, the ride was popular, as this article from the September 6, 1952, issue of Billboard Magazine described:

An early Jeep train can be seen in this photo from a book called St. Simons Island by Patricia Morris, which was also made into a post card.  It looks like there might be a jeep all the way in the reason, too.

 The use of a CJ-2A was followed up in 1955 (or later) by a CJ-5. This image can be found at this website:  http://ga67.herobo.com/island6.html

Mr. Long arrived at St. Simons in the late 1940s to take over the stables there.  He managed these for decades.  The land (all or most of it?) on which the stables were situation has been turned into  the St.Simons Land Trust.