I just circled Japan on a Princess cruise ship. It was a great way to tour the country

It is as breathtakingly beautiful as it is hard to reach.I am wandering through the fairytale-like Japanese mountain village of Shirakawa-go, a famed UNESCO World Heritage site, marveling at its picture-perfect, gassho-zukuri farmhouses.Built without a single nail, the centuries-old, soaring-to-the-sky thatched-roof structures, which sit amid strikingly vivid emerald-green rice paddies, are a sight to behold — Instagram-worthy relics of a Japan that's now mostly lost to time.I am also marveling at the fact that I am even here.Located in Japan's remote Sho River Valley, Shirakawa-go is hours away by car or train from such Japanese tourist hubs as Tokyo and Kyoto — far enough that most short-term visitors to Japan wouldn't normally have the time to get here.Shirakawa-go is a UNESCO World Heritage site. GENE SLOAN/THE POINTS GUYBut I am not traveling around Japan by car or train, nor am I relying on my own planning to explore.I am touring the country — indeed, circling it in its entirety — aboard a Japan-based cruise ship: the Princess Cruises vessel, Diamond Princess.As I am seeing firsthand during my visit to Shirakawa-go, which is just over an hour away from the port where the ship...