You can take the bus to MGM and then the ferry to the boardwalk or you can walk on the pathway from MGM. I have found that it is faster walking.
To get to Fantasia Gardens take the boardwalk to the end between Atlantic Dance and Jelly Rolls Piano Bar. Cross the bridge toward the Walt Disney World Swan and Dolphin and continue straight ahead to the street. Fantasia is on the left and the tennis courts are on the right. (If the big tent is set up, guests may walk through the tent.)
You can get to Winter Summerland by taking the bus to Blizzard Beach, and then just walk over to the Winter Summerland