Hey Laurie!
Historically, Saturday, Sunday, and Monday are the busiest days at Magic Kingdom Park. This can change based on Extra Magic Hours and other Special Events, but the weekends tend to be the busiest as many families like to start and end their magical vacations at the home of Cinderella Castle.
May and early June are both great times to visit Walt Disney World. The weather is warm, but the summer humidity hasn't fully set in. The first two weeks of May will have slightly lower crowds, as the majority of schools are still in session. You also get to experience the
Epcot International Flower and Garden Festival. Epcot is transformed with thousands of flowers and amazing topiary displays featuring your favorite characters. It's truly breathtaking to see Epcot in bloom. It's one of my favorite times of year to visit Epcot and makes for a magical Mother's Day.
However, if you have any Star Wars fans in your family, you may want to consider visiting the first week of June and experiencing the final weekend of
Star Wars Weekends. Star Wars Weekends take over Disney's Hollywood Studios Theme Park on select weekends in May and June. They feature parades, special character meet and greet opportunities, celebrity experiences, limited edition merchandise, and much more. It's a celebration that's out of this galaxy!
You really can't go wrong with either choice, Laurie. I hope I helped make the choice a little easier for you. Please let me know if you have any other questions.
Ashley