Japanese long distace trail - the Tōkai Shizen Hodō

I'm thinking about heading to Japan for a few months (April to June) & was wondering if anyone has done this thru or section hiked parts? Its roughly a 1000km trail, from Osaka ending on the outskirts of Tokyo.

There's not much info out there in English, except for a few blogs of people who have done it. It should take about 5-6 weeks (plus/minus sightseeing days around Kyoto etc), but I was wonding if I should instead spend more time in the Japanese Alps near Nagano (there's supposed to be some good multi-day to week long hikes around there) & maybe even up to Hokkaido instead?

Any thoughts/feedback would be appreciated.

https://en.wikipedia.org/wiki/T%C5%8Dkai_Nature_Trail