There was someone who just posted on the Resorts board about either YC or BC... can't remember which. But they reported that bus transportation for them was just fine for them. You'll find people on both sides of the river... but usually the folks who have no problems stay more quiet.
Travel times can vary by driver, my personal experiences put an average of 10-15 minutes to the MK, depending on if they stop at the Boardwalk.
Downtown Disney is a different story, because there are multiple stops within the DTD area. The bus ride could be anywhere from 12-25 minutes.