Ok, Ill go, think I can make it if I start driving now?? I havent been to Korea for a TEAM SPIRIT exercise since 81 anyways!
If cult leader Sun Myung Moon had his way with his crazy idea some years ago, there would have been a bridge between Kyushu (Japan) and Pusan (Korea). Therefore, your only problem really probably would be getting across Alasaka, then the Bering Strait (by ferry?), then again by ferry across the Ohotsk Sea after you had come down the Kamchatka Peninsula, to Hokkaido.
What a drive! Maybe two months?
On second thought, get a cheap KAL R/T coach fare from a West Coast city and stay in a youth hostel in Korea to cut costs.