We were at Epcot on Monday and MK and AK yesterday. Epcot was crowded but manageable. MK yesterday afternoon was a total zoo. LL lines were long and spilled out of the queues in most cases. The Peter Pan LL queue stretched all the way back to Philharmagic. Standby for Haunted Mansion reached all the way to the riverboat dock. Got fed up and hopped to AK, which was still crowded but better than MK. The guest relations CMs at MK said Wednesdays were the worst day of the week during party season.
If you are not going to the extended evening hours, avoid those parks. Do MK (or DHS) on a party day if you have park hopper tickets for lower crowds. Pack your patience.