Hi Maria,
Congratulations on your upcoming graduation, you've picked the perfect place for your celebration! If you are looking for a great experience, that is a whole lot of fun....I highly recommend you try will generate life-long memories I would highly recommend you try a Segway tour. I have done the
Around the World at Epcot, and had an amazing time! They also offer a
Wilderness Back Trail Adventure for even more excitement!
As for which days of the week to visit each park, these are my suggestions (based on your summer vacation):
Magic Kingdom - Sunday or Friday
Disney's Hollywood Studios - Monday or Friday
Epcot - Saturday or Sunday
Disney's Animal Kingdom - Monday, Tuesday or Sunday
I will also add that if you can avoid the park that is offering the Extra Magic Hours each day, you should find the lighter crowds.
Hope this helps!