I recently watched the entire extended trilogy in one day at the cinema. There were only two pauses. One 15 minutes long after the first movie and one 30 minutes long after the second movie in time for dinner.
This is how I saw part 3 in the cinema at opening. The cinema had part 1 and 2 extended on the day leading into launch and just after midnight we watched part 3.
… Is there any other way to watch them?
So I have done a weekend of the Saturday being all three extended Hobbit films and the Sunday being all three extended lotr films
Needless to say, I’ve got zero desire to ever do the first half again
The 2nd day was fun in spite of the first though