To get to the Yachtsman Steakhouse from Epcot, go out the International Gateway (between UK and France). You can catch the boat from here or walk. The launch goes from Epcot to BW the to YC/BC, so get off on the second stop. If you opt to walk, when you come to the bridge over the water way keep going straight. You can either duck into the Beach Club and walk through it part of the way (a bit more walking, but inside an air conditioned building) or stay on the path to the Yacht Club. Overall it's about 0.4 miles from IG to the YC lobby.