Archived:ThreePlusOrMinusNGaijinInABoat

To be a plan to get to Japan without all that tedious mucking about in siberspace
To include a trip to Korea, because all Japan and no non-Japan makes Jack a dull weeaboo
To be of duration similar to PlanN
To have an aeroplane at both ends of it

The "Beetle" ferry goes from Fukuoka, Fukuoka (so Asian they named it twice) to what we are now supposed to call "Busan" in S Korea. But as the United Nations could tell you, it is a bloody long way from Pusan to Seoul (see below), so if we are to go anywhere interesting in Korea it cannot be a mere day trip. Indeed I (Smith) can quite see Korea expanding into an almost equal partner in this putative coalition, because we may find that there isn't so much in Japan to, ah, occupy our attention (inb4 Manchuria)
I (Smith, though also valid for anyone) have not crafted an itinerary yet