Thank you for visiting us here again at the Disney Parks Moms Panel, David!
It sounds like you have a wonderful trip planned with the whole family - exciting!
Unfortunately, you would not be able to
upgrade to a Park Hopper for only one day, no. Even if you upgrade on your last day, you will be charged for the difference for the entire 6 day length of stay. It would still be less expensive to do the upgrade for that one day than to purchase a separate one-day Park Hopper ticket, though!
I love the idea of doing the "greatest hits" on the last day there, that would be fun. Have you heard about
Express Transportation, a new option to get from park to park QUICKLY? I just used it on my last trip and I absolutely loved it. I went from
Epcot to
Disney's Hollywood Studios in ten minutes, and you bypass having to go through security again. I would definitely check it out!
Have a magical time!
- Jan K.