Japan late spring/early summer

Hi,
I plan on visiting Japan again next year, prefered somewhere around end of April or early May.

As Golden Week springs to life in late April / early May, I am not sure when exactly to leave.

I went last time in late March, returning in early April.

I want to take a few days to visit Hokkaido as well. When I went to Japan in mid May, I think it was still rather cold when visiting Sapporo in late May, but maybe it differs a lot. The sakura blossoming was quite delayed as well.

Arriving a day or two after the end of Golden week would seem to be the sensible approach.