Gillian,
Thanks for asking your questions to planDisney!
To begin with, I always recommend that the moment you purchase your theme park tickets that you make your theme park reservations, with the Disney Park Pass System. Specific to one of your questions, yes, you can change those selections as you get closer to your visit, though you would want to be sure that the park you were moving to had availability on that date. Here are the steps you will want to follow for that change.
- Start by confirming that the park you want to switch to has availability, based on your ticket type, for that particular day. If there is no availability, you will want to keep your original reservation.
- Next, go to your My Disney Experience account and select "My Plans". Find the theme park reservation on the day that you want to change and click on "View Details". On the next page, you will want to click on "Cancel This Reservation", selecting all the guests for whom you wish to cancel.
- Finally, all you must do is go in to make the updated reservation selection, as you did before, with your new park selection.
As for making dining reservations, the app should let you book your dining wherever you choose. It does so, because it won't know if you plan to park hop to a different theme park for a meal. Also, you could be leaving your primary park to eat at a resort, then return to that original park. So, you are good to book wherever you wish.
BONUS TIP
A dining reservation does not ensure entry into a park. If you have a meal reservation in a park that you are trying to hop to, but you are unable to get in because the park had reached capacity, you will not be able to get into the restaurant. So, plan accordingly!
Write me back if you have any other questions.
Have a Magical Vacation!
Doug