What are you planning to force him not to ignore that area?Because what if there is another way to delay the US counteroffensive? What if there is a way to force the US player to leave the script and fight in another area, completely on Japanese terms, where half of the year is invasion-proof? Instead of fighting very close to major bases or even supply sources, perhaps it is possible to force the US player to fight in dreadful conditions with few built-up bases, and without any cover for his own SLOCs other than his CVs can provide? Isnt that better than fighting the entire Australian or Indian army over terrain that ultimately never can be held for more than a short period of time?
Why should he care about the Jap sitting in Anchorage?