AA nl 20

Bet the turn. He will call you with >77 and probably a lot of Ax hands as well, though obv he doesn't have those nearly as often. He shows up with a random T or 6 sometimes because he has a huge VPIP but he will call really wide on this board IMO.

If I bet ~$6 on the turn, I would have pot size bet on the river. Should I bet that big? (150bbs total)

Bet more PRE / since you are OOP and fishy players like this will call +1-2/bb more. cx/f Turn ( he have pretty low AF I know sample is really bad but I think he would cx back turn w/ Ax ) cx/call River since he might bet River with any Kx + Ax ( ax here for value )

Since our isolation range usually isn´t Tx I think we can´t bet all 3 street for value and expect to get called down weaker hands, so I like going pot control on the turn and calling him down or if he checks then bet river. I personally think he is just bluffing river, since why should he ever check back turn Tx or 6x on the turn and since K is good barreling card he can turn smt like 77 or Ax hands into bluff.
And personally I don´t like folding aces against 77/29 player. You should be ahead just too often to make b/c profitable. With reads it is always different story and you can safely b/f river if you know he isn´t able to make bluffraises.