From BLT your best bet is to either take a cab to the Boardwalk, walk over to the Magic Kingdom and grab a bus to the Boardwalk, or take a DHS bus from BLT then walk over to the Boardwalk from there. Taking the monorail you would be dropped off at the front entrance of Epcot and you need to go out the back gate (World Showcase entrance) to walk over. Hope that helps!