Uhhh.. not that unorthodox i think. Sources are in hungarian, i dont think you could go anywhere with Bánlaky"s Magyar nemzet hadtörténelme or Négyesi Lajos about the battle of Muhi - but the later one i find interesting, i will try to translate and summarize it - and various small artickles about the battle and the invasion inlocal (historical) papers.
(The pirmary sources are usually Rogerius, Thomas of Spalato, the letters from Béla to various persons and vica versa, and Subotai's life fromt the chinese and chinese yearbook).
Unless I'm much mistaken/confusing you with someone else, you were the one questioning that the Mongols left Hungary due to Ogedei's death. That's pretty unorthodox to my knowledge.
About upper hungary, its today slovakia:
http://keptar.oszk.hu/009100/009138/hungary_1241_nagykep.jpg
Above you find the link to the "accepted" map of the destruction.
(the level of destruction diffes of course, for example in the transdanubia the mongols did not have the time for real razing - they were after the king after all)
Thanks.