Of course, if you do get "Rule 80'd" over to JL, be sure to use the "involuntary reroute" phrase to get original miles and points if they don't post automatically.

Does AA use the Excel Tokyu Hotel (adjacent to the Hilton?) If so, they share a shuttle to town with the Hilton, and Narita-shi actually can be a pleasant place to hang out and wander (rain makes it a bit less so.) Easy day trips to Boso-no-Mura or Sakura. Mike Newman's Narita Layover Page (aircrew oriented) is a good resource.