I’d go with the 22". The smaller 16" and 14" Webers aren’t really any all that much more portable that the full sized ones. Weber’s charcoal stuff is pretty compact and lightweight to begin with. Particularly with the basic models. You basically save a little bit on foot print and a bunch on hieght.
And you run into capacity issues. You might think to yourself “when am I ever gonna cook that many racks of ribs?”. And you’ll probably be right on that front. But then you find yourself hacking certain cuts like brisket or turkeys into pieces just to fit them, its more of that size problem than total capacity.
Its less of an issue with the bullets than the kettles. And a VW van is the sort of camping where that storage space difference could be important. But otherwise there’s not a ton of difference in transporting these things till you drop down to Smokey Joe.
They used to make a Smokey Joe branded bullet, I think it became the Smokey Mountain 14" with a little more hieght. And there are after market inserts if converting a pot is a no go.