We've done a couple spontaneous trips where there was no way to book fast passes in advance of a day or two. The chance of replacing for a "roller coaster" like ride is impossible. Here's what we do:
- All other rides will become walk on at some point. we plan to walk the park twice. Some area is short wait and walk on, we just dont' linger when its not or we find ourselves in a crowd moving ride to ride. when we do find ourselves in a crowd, we check the wait times on the app and figure out where to head to next. It's a great time to ride the train in MK for example to get elsewhere, get a rest and take in another "ride". Near ten minutes on the wait list means walk on since many rides takes 5-6 minutes to walk up to the ride, wait for it and get on.
- We only try to switch individual rides and not the full set and we only change don't really care about/could do without rides.
- As we use fast passes, we always try to adjust the next one sooner since it'll pop up a previously overlapping time slot you couldn't get before. This works best if your 2nd and 3rd have a gap because times are considered an hour to use and you might not be able to fit in the next one before the following start time.
- If there is some ride we just couldnt' get on, we ask the hotel near the end of the trip and more times than not, they just add it as a fourth fastpass for one of our last days there. It has to be available thoguh, but they have some wiggle room in this area that you don't. The more deluxe the hotel, the better the chances (in our opinion) but we can't confirm this.
- The cast members with a tablet (not the gate entrance ones) also have that fourth fast pass option. Generally they wont' use it unless a ride was down for weather or problems a lot that day but never hurts to ask.
A ride trick that is handy:
- Some rides have more than 1 track, if your hear broken or shut down don't be so fast to rush out of line and let everyone else get out of your way. Rain is another story and oyu have to decide since it has to stop raining and clear up first to restart the ride.