Good luck on your new club (not a chapter, that would be a subset of a larger club and I am pretty sure RI is not near large enough to have chapters). It takes an ass-load of work, but can be very rewarding. Most of my best friends over the past 14 years are a result of the Bronco club I am in.
When I founded MEB about 14 years I ago, I attended many shows and started to collect names and contact info. I soon realized that PA was not large enough to support a full fledged club, so I expanded my focus to the entire Mid-Atlantic region which gave enough interested people to get Mid-Atlantic Early Broncos up and running. We actually pull members from an area greater then the physical Mid-Atlantic region since our members typically are from about 10-12 states. The Bronco density out here is just not dense enough for smaller, local clubs as it is in SoCal and some other area. Even having been one of the most active clubs in the country now for over 13 years and having members from over 10 states, our annual membership is still only occasionally approaches 200 and is more typically 125-150.
Having enough people in an organization is key to keep enough people sharing the work and to keep the cash flow from dues do the club can do fun things and have some money in reserves to bankroll the upfront costs associated with many of the events such as MEB puts on (East Coast Bronco Roundup, Wrench & Roast, Fawl Crawl, Fall cruise, etc.).
The key is to get a good, reliable core group who are willing to work hard at it and to get some fun and unique activities planned for all to enjoy.
You also need to get your by-laws established, get incorporated, set up a bank account, and all that other fun stuff to make it legit and to offer some protections to those running the club.
If you have any questions you can shoot me a PM.