We were only there for two days recently, so the only parks we visited while there were MK and Epcot.
We used the boat for MK and loved the convenience. It was a lovely change from using the bus.
We never waited very long for a bus to Epcot and we didn't experience any overcrowded buses, but the bus trip took longer it seemed than any other resort we've stayed. Part of that is due to making a stop at Fort Wilderness. We didn't mind that though as it gave us a chance to peek at that property!