I thought he was supposed to have the power to unmake the world from the Big Bang to the end of time... or something along those lines...
Wouldn't he just grow back whatever gets destroyed a la Renegade Doctor...
Actually, this might be possible. I know pretty much nothing about RKT, so I might be wrong, but at his better showings, The Doctor is quite possibly beyond Skyfather.
Still, the cards are with Thor here. His magical-ness, I'm assuming, would prevent him from being turned into a tree or somesuch. And Jeroen would need to pull out his A-game. His magic has been known to "slide through" more powerful entities, and RKT might be one of those.
But...
Make them both travel to his home dimension....
Grows hismelf to the size of a mountain, with the strength of a god....
Slows down time to buy him some time against Thor...although he might be able to counter this as well...
TKs everything around Thor across the dimension (Mjolnir would return but it would buy him some time).
Has everything attack Thor simultaneously (physical constructs within the dimension as well as trying to hurt him normally via punches/energy attacks/etc.).
...also floods him with the thoughts of past Doctors to hinder and confuse Thor while they battle.
...pounds away mercilessly physically and telepathically...
...
Like I said, his A game. RKT still takes probably 8/10. But Jeroen (or any Doctor) could do it in theory.
No one wants to tell me why I'm wrong?? Maybe I'm not, but I'm guessing I am. Either that or everyone's too scared to face me while I defend the Doctor.