I much prefer Tokoyo to Seoul. Areas of Seoul are walking/walkable but not the city as a whole. I didn'tfind any great food,or shopping, or history - didn't look for nightlife. Taxis were inexpensive (4 yrs ago)and subways easy but no real exciting places to visit. Koreans treat westerners well - same as Japanese. I didn't find either group especially friendly but I believe it is more shyness and lang barriers US still has troops stationed in Seoul so they see Americans.

The DMZ is more of 'I have been there' place but nothing exciting to see IMHO - just a strip of barren land with fences etc. My favorite in Seoul was the baths. I'll take Japanese cuisine any day compared to Korean. Maybe you should explore a 2nd location in Japan. HawaiianTraveler has many posted trip reports and information re Japan. Consider a 2nd place in Japan that is interesting but different from the huge city of Tokoyo. I may go back to Seoul someday ONLY if the routing of an airline sends me there but not as a Destination. Is Tai Pei or the Phillipines within reach? I'd check and see. Actually - what an interesting 'problem' to have. Let us know what you chose.

Wintersp, thank you for your reply. It is very helpful. What you wrote about the DMZ confirmed one of my suspicions (what I am really fascinated by is the idea of going to North Korea, something I really want to do, but am somewhat fearful of). Fortunately for me, a few years back I did a lot of business travel in the region, and Taiwan and the Phillipines were visited multiple times; no need or desire to return now.

I am leaning towards doing exactly what you said, doing Tokyo, and adding a day trip(s) to Kyoto or Tokyo to explore some new place(s) in Japan.

Check the weather. I think it is rainy in Japan in Sept. There would be a sumo tournament in Tokyo.