After 2 weeks in Honshu, we are spending the 3rd week of June in Hokkaido. This our first trip to Japan (Husband and 18y/o son). I’m looking for suggestions on where to go/ what to see in Hokkaido, how to best spend our allotted time. Thanks!
Hokkaido in late June is a great choice, as the rest of Japan will become hot and humid. Hokkaido is famous for onsens (soaking hot springs) , excellent seafood, and natural scenery. Since there are the three of you, you can opt for renting a car when you are not staying in major cities (Sapporo and Hakodate). There are some sleeping volcanoes by lakesides, where nice resort hotels are located. Have you checked out https://www.japan-guide.com/ and https://www.visit-hokkaido.jp/en/ ?
I want to add that renting a car in Japan is very civilized and stress-free. The agents won't rip you off for "damages" that you never make. Drivers there are polite and sane.
As mentioned, it does take a while to get used to driving on the opposite side of the street and reading speed signs in metric.