The experience isn't particularly draining. It's not like it's outside in the hot sun. You're air conditioned, and while what you've heard about the food is true, if you take your time to enjoy it best you can (as opposed to many people's habit at buffets of stuffing themselves as much as they can, as FAST as they can, until they can't move in order to "get their money's worth") it can still be pleasant. How long it takes for the entire group to make a route around the floor can vary from meal to meal. Last time we went...I suspect maybe one of the CMs playing Goofy called out sick because we saw Goofy on the floor, then after the song where everyone waves their napkins around, he disappeared for quite a bit and then came out just as we had given up and started packing it in. But usually, it takes about 45 minutes max. It behooves the restaurant to keep characters circulating, as some guests treat a pic with each character like Pokemon, gotta collect them all, and will stay an hour, or more, until they see every character. This means more of a build up waiting on tables, more unhappy guests, potentially more CMs having to stick around to keep serving and they can't really close the joint until everyone's fed and gone. So they'd rather keep things moving so you split.