James David,
Thanks for asking your question to planDisney!
As I am sure you know, you must make a Theme Park Reservation using the
Disney Park Pass system for your first park of the day. But there is no need, or way, for you to make a theme park reservation for the park that you want to hop to in the afternoon. The system only works for reserving that first park of the day.
But how do you know if the park you want to hop to has room to accept you? All you need to do is call
(407) 560-5000. That is the Park Hopping Hotline (or at least that is what I call it!), and they will indicate on the recording there if any of the parks are at capacity and are no longer accepting guests that do not have an initial Theme Park reservation for entry.
Needless to say, I recommend that you save this number into your phone for use on your park days.
BONUS TIPThe Disney Park Pass system does not apply to the Water Parks. So if you want to visit
Disney's Typhoon Lagoon Water Park or
Disney's Blizzard Beach Water Park, you can go before or after your Theme Park reservation, or on a day where you don't even have theme parks in your plans!
Write me back if you have any follow-up questions.
Have a Magical Vacation!Doug