The following resorts have
water transportation:
Yacht and Beach Club: Epcot 10 minutes, Hollywood Studios 15 minutes
Boardwalk: Epcot 5 minutes, Hollywood Studios 20 minutes
Contemporary: Magic Kingdom (walking is often faster)
Fort Wilderness: Magic Kingdom 15 minutes
Grand Floridian: Magic Kingdom 10 minutes (monorail is faster)
Old Key West: Downtown Disney 15 minutes (bus is faster)
Polynesian: Magic Kingdom 5 minutes
Port Orleans Riverside and French Quarter: Downtown Disney 20 minutes (bus is a little faster)
Saratoga Springs: Downtown Disney 7 minutes
Wilderness Lodge: Magic Kingdom 8 minutes
Please note that in transit times are approximate. Unless otherwise specified, the boat is usually faster but depends on weather conditions. Also when the monorail stops running (for unforeseen reasons) the ferry boats for the Magic Kingdom resorts get very backed up. This happened to us on our last stay at the Grand Floridian.
Otherwise boat travel is very pleasant and can be part of your adventure. In the off-season, it can be quite chilly out on the water. Most of the in transit boat times are faster than the buses. Smooth sailing!