LOL, yeah I'm asking a bunch of Disney addicts if a long stay is too much!Anyway thanks for the feedback so far, keep it coming!
I don't have too much in the way of ideas of non-park fun. Sitting on the Poly beach watching fireworks one night is on the list, and I wouldn't mind getting over to Ft. Wilderness for the Chip 'n Dale campfire. And just doing some of the free (or cheap) activities around whatever resort we are at (movies by the pool or one of their craft projects). I for sure want to get to Disney Springs as we haven't been since it was DTD (just did not have time/energy on our last few trips). I'll probably make a list and let DD and DH pick some things as well.
We are from UK and I would agree. It takes something special for me to spend 9 hours on a plane...I think it also depends on the age range of your party and how many days you typically vacation at others places. Disney is HOT most of the year and involves a LOT of walking which can be exhausting if you aren't used to that. Even if you take a few days off from the parks, 12 days sees like a long time to be there. There are also the practical aspects of how much clothes to pack for that long and/or are you planning to do laundry?
OP shows she is from USA, so it isn't like someone traveling from overseas where longer trips make more sense due to the amount of travel involved.