You could take the Fort Wilderness bus from any of the theme parks, TT Center, or Downtown Disney. If you are at the Magic Kingdom you could take a very pleasant boat ride over to Fort Wilderness. This boat also goes to WL. There is no easy way to do it. Going from one nonmonorail resort to the other without a rental car is very difficult. If you are going for the campfire you may want to try dinner at the Trails End at Fort Wilderness. It is very good and a bargain for a Disney restaurant