Had you seen this guy play a lot? Do you know how he plays AK? Does he normally re raise PF with it? If he does usually re raise then it may be more likely that he is holding AQ or AJ. If you can eliminate AK then it makes your decision easier.
AT is a possibility especially if he is holding the Tc but I think this is unlikely.
I also don't believe he has 77 because I'd imagine he'd put a raise out on the flop and would likely be more scared of the turn card.

I would check call the river and fold to a signifcantly large bet because in all honesty I think he has the big full house.

I'm interested to see what he's got!