I think that the US should withdraw all its forces from Japan and South Korea, and base the units in question in Alaska, Guam, Hawaii, and perhaps in Australia. This would generate economic benefit for the US communities where units would be moved to; and demonstrate that Japan and South Korea should take a greater role in their own self-defense.
The Seventh Fleet could be based at Pearl Harbor in Hawaii, the 3rd Marine Expeditionary Force (III MEF) from Okinawa could be relocated to Hawaii as well, and USAF wings in Japan could be based in Alaska.
Here’s a description of US Forces Korea(from Wikipedia):
The Eighth Army could be based at Fort Lewis, WA; the Seventh Air Force could be based in Alaska, and the others could go to Hawaii.
I think it makes a lot of sense.