> Here in Japan, some remote islands, you can travel overnight boat.

I'm sure there are many overnight ferries all over the world and I can't say I have traveled with many, but one I can recommend is the overnight ferry from Ziguinchor/Senegal to Dakar – it's reasonably priced (for a foreigner), and the cabins are very comfortable and even include a shower!

Meanwhile, the 3-day ferry from Puerto Montt (central Chile) to Puerto Natales (Patagonia) is very expensive (> 500 USD per person for the most basic cabin) and very unreliable (expect last-minute cancelations).