Raise the flop. You want information as early as possible before you get to the expensive streets. His 2/3 bet on the flop (coupled with the PFR) seems to indicate a good A hand - which he is successfully representing. With AQ I would challenge that with a pot sized raise to make it another $15 to go. If I don't take the pot right there I go into "safe mode" and only call the smallest bets - I assume he holds AJ, AQ, AK or JJ.