As long as you don't leave when everyone else does the bus will be fine. They only get really jammed at park closings when there are so many people trying to back to their resorts. As somesome suggested, just take your time, walk around, shop, etc. By the time you get to your bus stop the worst will be over and it will be normal again. Also, last week the Beach Club and Yacht Club shared one bus while the Boardwalk shared with the Swan and Dolphin.
I agree with another poster that after a long day and a LOT of walking you really do not want to 1) monorail to the TTC 2) go down the ramp and up the other side to the Epcot monorail 3) walk all the way from the Epcot main entrance to the International Gateway. If it's cool out it would be nice....but not in the Florida heat!