I was not defined as being a regional meet up, there are already some of those around including Vintage trailer rallies.
This was defined as a Seattle meet up which while a large area extending from Everett to the north and Tacoma to the south and Issaquah to the East is not what one would call regional other than Seattle being in the middle of it. There are regional meetups but this was intended to be a local meetup vs regional.
There are campgrounds within that geographic
area or right along the edges of it that don't require ferry rides (which are not just about the money but also about the hassle of wait times on the weekends) or 100 mile long drives.
Part of the reason for wanting a local meetup vs regional is finding nearby neighbors who can lend a hand now and again with projects or give hands on tutorials, help with analyzing troubles by being there seeing it in person, etc. That is on a daily basis very useful networking plus there is always the chance for coffee dates of the type "come on over to my trailer for a visit " which is a fun afternoon break vs time required for camping events.
Sounds like there is a second zone ready for a local meetup with Whidbey, Anacortes, etc being close to each other.