We have been two years in a row at this time, arriving on the Friday night following Thanksgiving. The parks are quite "empty" starting on Sunday as the majority of the Thanksgiving crowds are leaving! Saturday in Epcot was fine both years but we made the mistake of going to HS briefly and it was a madhouse. Otherwise the crowds were great for the rest of the week, we had blue skies every day and on our AK day FoP averaged a 75 minute wait all day! Only go to MK on party nights (but plan on leaving by 5) because non-party nights are a zoo. We left right before Pop Warner but I hear that it does not really affect crowds, just your stay if you choose a value resort.