6-10 am and 3-6 am were great last year.
Not going to lie rope drop was crazy but we were at the bus stop at 5 and at the park - we opted to split up because the bag check lines were a little crazy. I took the bag and sister's purse and went to bag check, she took DD and they went into the center of the crowd. There was no way I could get back over to them in the 10/15 minutes we had left so we just meet inside by City Hall. We walked on a lot/very little wait (but we didn't go near Fantasyland) and then left for a late breakfast at Ohana. Original plan was to come back for the fireworks, but we had a late night the night before and napped a little longer than we expected after the pool time. We made it back about 10 and went to Fantasyland. While we were there we hit everything SDMT (we did that later in the trip).
If you are going to do something similar to this book your FP+ for later in the evening 10-11-12, etc. We changed all of our FP+ as we were heading out to breakfast and it worked perfectly.
Have fun - it was an amazing day!