As others have said, any of the Epcot resorts are fairly close to DHS. The YC/BC are probably the furthest. The BW is the closest for walking (0.8 miles or about 14 football fields). The Swan would be the next closest (0.9 miles), with the Dolphin only being slightly further.
In terms of the boat, the Swan/Dolphin are the closest. The boat goes from Epcot to BW to YC/BC to S/D to DHS. So the S/D is the last stop on the way to DHS and the first stop on the way back from DHS.