Hi Larry ~
I LOVE the way your Grandson thinks! That is my answer every time someone asks me where I want to go too. Thank goodness my boys love Disney World as much as I do.
There is a link for information for
attractions on the Disney World website. It is broken down into categories. The fourth column lets you select those with minimum heights requirements. It has options for different height requirements. You can also find height requirements on the web page describing each individual attraction.
I would recommend that you measure your Grandson just prior to your trip. Then discuss which attractions he is tall enough to ride. If it is close, tell him the Cast Members have the final word as to whether or not he will be able to ride and prepare him for that (just in case). They sometimes measure Guests in more than one location (at the beginning of the line and closer to boarding) so be prepared for that as well. I've seen Guests make it past the first Cast Member and get turned away by the second.
I always tell my boys that we're very fortunate to live in Georgia so if they are not tall enough this trip, we're close enough to go back soon when they will be a little taller and can hopefully ride next time. This helps to avoid disappointment and meltdowns once we reach the parks.
Please feel free to visit us with any other questions. It is our pleasure to assist you!
Wishing you minnie magical memories :-) Allison V.