MSTA has been around since the early 80s. It's an all-brands sport-touring club with about 1800 members. They are best known for their regional rallies which feature group rates on the host hotel, inexpensive registration, excellent suggested backroad/twisty routes in both map & gps file formats.
Day rides are done in small groups, typically 1-6 people of similar riding skill. Regardless of your desired pace, there are suitable people to ride with. There is a designated 'MAP' person to help newcomers find someone to ride with.
There is camping available at events but this is mostly a hotel crowd. Event attendees don't come just to socialize- every day almost all are out riding routes.
Have been a MSTA member for 14 years & attend most of the rallies. Definitely going to Rapid City June 7-12 for the STAR national rally!
Other MSTA events on my calendar:
Fools Run DS ride, Tellico Plains, TN, April 5-6
N. Ga Classic, Helen GA, April 26-27
Twistar, Spring Green WI, May 17-18
TriSTAR, Sparta, NC, May 24-25
Big Lynn Lodge, Little Switzerland, NC, July 26-27
River City Ride, Corydon, IN, August 3-4
MailPouch Fly-By, Marietta, OH August 2324 (Biggest & best MSTA regional rally)
Bull Shoals, Theodosia, MO, September 6-7
Fall Colors, Lewisburg, WV, October 4-5
For the regional rallies, I usually leave & ride to the rally hotel on Thur, ride local routes on Fri & Sat, then come home on Sun. Living in Dayton, OH, the above rallies are 200-650 miles away so it's not hard to get to them in one day.
If you like sport-touring on great twisty roads, this is the best group I've found.