We live in Indiana, so a 1-night trip down could easily cost us $600-800 with round trip air for two, a hotel night, tickets, and food for 2 days. I've been going since 1986, so I've lived through many ride/show/attraction closures. If we know well enough in advance, we'll experience something on our next trip, if it's before the end. For example, we knew Maelstrom was closing, so we rode it on our August trip. And when we knew Snow White was going to go away, we rode it too.
The Backlot tour was one of my favorite attractions....in the 90s. Since then, I've only ridden it out of nostalgia, and we completely skipped it in August because of the horrendous heat. Even though the ride was awful, I feel like I didn't get closure with it. BUT, I would not have paid hundreds of dollars to experience it one last time.
The things I wish I could have experienced one last time before they closed include 20k, Skyway, Horizons and World of Motion. Again, I probably wouldn't spend that kind of money to fly down on their last day....but if I did, those would have been on my list.
Now, if they ever hint that something like Tower of Terror will be closing (I don't see that happening.....ever), my wife and I would be on the next flight to MCO.