As the actual cost will most probably be the main concern for all, going by comments from other threads, the "best" destinations would likely be to big tourist cities. Flights would be priced cheaper to hot spots as opposed to "why are we going there?" destinations.
Also, pricing for accommodations/travel arrangements for groups would likely be more economical where there is competition.
????????? Just my thoughts as I read this thread. Sounds like a GREAT thing to plan. I've read the Elm Creek series, actually have them, and I never knew there were such things as retreats. Didn't know a thing about quilting either, except that I was fascinated by them, until reading them.
I so don't want this to come across in any way as offensive.