As the PPs have said, you have two choices:
1. Walk (exit via IG and follow the path to the BW and then onto DHS). It's 1.27 miles from IG to DHS. So depending on how fast you walk, this might be quicker or slower.
2. Boat. The boat goes from Epcot to BW to YC/BC to S/D to DHS. The ride is between 25 to 30 minutes depending loading times. If you get there just as the boat is leaving, you might make the trip in about the same time. If you just miss the boat, then you may have wait up to 20 minutes for the next boat to arrive, load and depart.