For MK, if you are staying in the Tahiti or Rapa Nui buildings (the mist easterly) the TTC and then the Express monorail is the fastest. The more westerly you are from there the more efficient the resort monorail in the GCH becomes. We always take the resort launch though since its about as fast and it's next stop is MK.
Regardless of building, the best way to Epcot is to walk to the TTC and take the Epcot monorail. The resort monorail take at least 15 minutes to get to the TTC (not including the wait for it at the GCH) and the walkto the TTC is 5-7.