PS: This now applies to Islands of Adventure at Universal as well. I don't know what it is about castles that make people beeline towards them lol
Avoid whichever parks have Extra Magic Hours on that day. Right now, that means no Animal Kingdom on Monday morning, no Epcot on Tuesday morning, No Magic Kingdom on Thursday morning, and no Hollywood Studios on Saturday morning. (There are Extra Magic Hours in the evenings, too. But those tend not to affect morning attendance as much, and I always urge people to get to parks early.)
So I'd do Hollywood Studios on Monday, Animal Kingdom on Tuesday, Epcot on Thursday and Magic Kingdom on Friday, figuring that the hotel crowd will move onto another park the day after its Magic Hours day.
Extra Magic Hours can throw things off depending on when you visit.
I always found mid-week (Tues,Weds,Thus) the best days to go to almost any theme park provided it's not near a holiday.
Walt Disney World's Magic Kingdom
Disney's Animal Kingdom
Disney's Hollywood Studios
Disney California Adventure
Universal's Islands of Adventure
Universal Studios Florida
Universal Studios Hollywood