Not sure of the timing of your ADR relative to fantasmic but you can get from Epcot to DHS without a whole bunch of buses. You would exit Epcot thru the international gateway and walk to DHS. It's supposed to be a 15 minute walk from the BC to Epcot and 20 minutes from BC to DHS. There may be a shorter way to walk this - I've not tried it. Or you could go to the international gateway and catch the boat to BW and switch boats there or walk from there to DHS.