Your question was do they ALWAYS begin in Pahrump?
So far that is true because last fall was actually the very first one HOWA was involved in facilitating by planting flags at locations suitable for people to gather in.
This fall, in October, the first HOWA facilitated caravans of the season are likely to begin in Pahrump sometime in October. Nothing is going to be published about it until September.
Of course you are welcome to start up a caravan before then. You can use the We Camp Together Facebook page to invite people to join you at whatever location of tour choice to begin it in.
This summer some of the people who met in the first caravans of last year are still traveling together meeting up at various locations. But that is not a formally arranged or publicized thing. However that is exactly what HOWA hoped would happen, making new friends at the caravans who might become casual traveling companions.
In the meantime go on Facebook to the HOWA associated page We Camp Together and make friends there. Or go to the HOWA Meetup page and participate in the virtual caravans and make friends there.
Or start a thread in this forum to arrange a caravan.
What I am saying is use your own initiative to create one instead of just wishing to be in one. "If you build it they will come"