If you're asking what's fastest,that would be walking,the boat is just plain slow and has to make three stops and with walking there's no uncertainty how long you'll have to wait for a boat or for a bus to the front of Epcot.With that said avoid walking if it's hot out,it will wear you out.With young kids it's also not a good idea,even in cooler weather.If it's a nice cool crisp day I would walk back and forth all day,the Boardwalk area is beautiful,maybe you can grab a beer at Big River grill at the Boardwalk.