Supposedly, the caravan used to arrive here once an hour around the hour mark; but that schedule no longer applies, and the interval appears to simply be however long it takes to travel to the south and back. Vendor-Tron 1000 is only available for a short time while the caravan is stopped. If you get there late, it may even disappear while you are shopping. If you need one of the unusual recipes the it sells, you will have to wait (or return) for its return.
Of most interest are the rare cooking recipes (only one per stop) from this vendor:
Recipe: Carrion Surprise can only be bought here for the Alliance, whereas many Horde vendors have this recipe.