Recommend climbing Fujisan, I did Fuji a few years back, in September near the end of the season, watched the sunrise from the top. Bit of a journey getting there from Tokyo and back again but well worth it
I stayed at the 8th station, the idea is to sleep till about 3am and then hike to the summit but chances are you won't get any sleep, as you and everyone else is cramped into bunks and it's noisy as hell , farting, snoring , the usual.
At the top it was bloody wet and cold with a nasty cross wind so waiting for the sunrise wasn't that enjoyable, there is a cafe but with limited spaces so you can't stop long before you're back out into the cold . Got lucky in the morning for the sunrise and 'unkai' ( sea of clouds) though then walked around the caldera before hiking back down. Great experience, although would bullet climb it next time, missing out the hut stop.
It's not technical and as pointed out it's more or less a bit of a hike, the trails are designed that way to be honest. If you want to you can start right at the bottom, walking through the forest.