You will never satisfy everyone. Either the date is wrong, location, length of event , etc. I have seen many events never materialize when you try to keep everyone happy. THe best you can do is pick a date, pick a place, and set up some activities. If they like it, they will come. If it is too far, too short, or the wrong time of the year, they won't.
I think you have a great start. I'm planning on attending unless something happens, you never know. I applaude you efforts and keep it up!! Since you picked a tourist type area, they should not have much trouble with handling a large group for meals or ???