It also seems to me that you must have been assembling your substatial force for the Kurile/Hokkaido invasions while he was trying to conquer India. If you had done as most players would, a lot of that force would have ended up in India, stopping his invasion well before your Hyderabad [Sindh] line. Like the Germans in Stalingrad, it only looked like they might succeed because a massive counterpunch was being held back until it was fully cocked.
Honestly at that time(1942) i was just struggling to survive and wasn't thinking about an hokkaido invasion at all!
That said, i think that Rader's achievements could still be improved...he waited too many months before crossing the LOD, giving me time to build up my defences and probably was too methodical in his conquest....if he had gone directly to the throat ( say a landing at karachi) i fear that things may have gone differently.... I imagine a landing in the chittaong area first ( or Viza) ....the, while the allies are trying to stop the japs in the plains, a combined landing at attu- diego, bypassing cylon.... Then, while the japs are blietzkrieging in the south- east of India, another massive landing at Surat, bypassing Bombay.... From Surat the last leap....directly to Karachi....by the end of april 42... Sounds that fool?
from a game perspective it doesn't sound fool, from a game perspective you can also land 6 divs directly at Karachi with your next bigger base being Rangoon. But this is only possible in the game and is utter nonsense realistically speaking as in real life you need a line of supply, a working one. In the game, you just need to move halve a dozen divs somewhere and a couple dozen freighters full of supply and you can land wherever you want, even if it is 5000 miles away from your next base. These are those games that usually end earlier than later because one of the players went nuts, as I have seen it too often and experienced it myself just in my last PBEM when my opponent vanished.