I think Sammie's answer would be the same for Epcot, or MGM too. Factor in time for the parade, the walk out of the park and over to the bus stops... I would not count on being anywhere by 5 because of the potential mishaps. The bus ride from AK to any other park would be about 10-15 minutes but that assumes that the bus was right there when you arrived at the bus stop. If you just miss the bus, you'll be cooling your heels another 15-25 minutes. Keep in mind that AK is much further out than most of the other attractions at WDW.