Have you looked into 'workboxes' for structure for your ds? just google it, and you'll find tons of ideas. Not too hard for you to do, but lots of organization for him and a feeling of accomplishment.
that's awesome you're going to disney w/ a homeschool group!! have fun!!
as for you enjoying staying home... I'd then just enjoy your time home w/ the kids. Are they ok with this? there's nothing wrong w/ not being "joiners"... everyone has their different personalities and what feels 'right' to them.
What about the YMCA? cheaper classes or activities to do once in a while just to get out?
On another thread, someone wrote regarding a year they were home a whole lot, "a serving of friends on the side"... (I told her I was stealing that saying, because I think it's great). That sounds like all your kids need. Just a small serving. Don't worry about getting them out.
Hope it all works out well for you all