Interesting question. If you have a car, you must park it in the Campground parking lot and take a shuttle bus to where the show is. 15 minutes to drive to the lot, 10-15 minute wait for a bus, (maximum), 5 minutes on the bus. Just count backwards and you will see how much time to allow.
No car? Take a bus to Magic Kingdom then look for the boat to the Campgrounds. 15 minute (max) wait for a bus, 10 minute ride, 20 minute wait (average) for the boat, 15 minute ride in the boat. Do the math. Best thing about this is that the Hoop-De-Doo is a short stroll from the boat dock.
From any other park? The "Campground" buses go, I think, to the Campground parking lot. You still have to transfer as above, to the best of my recollection.
Cab? I don't know if taxis can go beyond the campground parking lot.