My 10 minutes to edit ran out, here's my amended reply (I had at first read it that the band was forcing everyone to pay 2 grand for a mandatory Diznee trip, that would have been insane)
The club/activity travel in and of itself isn't that unusual. The unusual part is the 'let's turn a Saturday afternoon performance in Boston into a 3-night, 4-day adventure!' aspect. That's very odd.
My daughters school goes out of their way to try to prevent staying overnight, because of the increased liability and need for additional chaperones/volunteers. I believe the only overnight event they have for orchestra (my daughter plays violin) is an 8th grade only trip to Springfield, but that's just one night.
As far as the 'class trip'... 6 days in Diznee seems a bit out there, but that really depends on the district and what kind of deal they cut with travel operator. For the sake of comparison, my daughters school used to do a school district sponsored 3 night trip to Washington DC... but after COVID they outsourced it to a 3rd party company and while the school will send an email blast out about it they are very clear that it's not an official school event and is completely optional. (my daughter does not attend it)
I'm guessing that the Diznee trip is entirely optional, occurs before the school year, and there wouldn't be any kind of punishment for not attending? If so, the school providing the trip as an optional event itself isn't that weird... the length and cost sounds a bit overboard though. I would definitely tell my daughter no dice on that (granted, she gets to to go to Orlando for cheerleading once every couple years anyways, so that would make it easy to veto the school trip)