The grad nite would be over and I believe the AP passes will be blocked. Trying to find the best time to go in June. I heard that the week after the 4th of July is good to me I would think that would be a very busy time.
End of June is about when Star Wars Galaxy’s Edge is projected/speculated to be open by so I wouldn’t plan for any “good” crowd times after Memorial Day weekend 2019.
That being said, I also wouldn’t not plan a trip to Disneyland (speaking as one who visits DL from out of town & bought an Annual Pass intending it to be a 1 yr deal only & just renewed it for the 4th time…).
I would just make sure to pack my patience & make sure I knew what were priorities to get done & plan for those things as must-dos early on in the trip. With everything else being gravy on top!
(I have also heard the week after the 4th is very great & have had friends there at that time who agreed. We have done right before the 4th & found it very easy to do. Unfortunately, Star Wars land next year throws a wrench in looking purely at historical data).