Fantasia Gardens is right across the street from the Dolphin Hotel. Here are directions from allearsnet:
TRANSPORTATION: Your best bet to reach Fantasia Gardens is to either walk from the Epcot resort area, or to drive.
DRIVING: Traveling west on Buena Vista Drive from DOWNTOWN DISNEY, turn right at the second Epcot Resorts Boulevard traffic signal. Traveling east from World Drive, on Buena Vista Drive, turn left at Epcot Resorts Boulevard traffic signal.
ON FOOT: From Disney's BoardWalk Resort, cut through the resort lobby to the Boardwalk. Turn left and continue 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.)
WDW TRANSPORTATION: You can get to Fantasia Gardents by taking WDW Resort transportation to the Dolphin, followed by a short walk from the hotel. If you take a boat to the Dolphin, go through the hotel to get to the parking lot entrance. It is across the street from here. If you take the bus to the Dolphin it's across the street. Either way, once you arrive at the Dolphin, inquire for directions. Use caution crossing the street on foot!