another hand against a foxwoods regular 5-10 NL

[McStinky]

This is a hand that I played a little weirdly, but it felt right at the time. Villian is this regular named Dave, who is always there playing 5-10 NL. He seems to think about the game and his opponents a lot (and talks too much), but still screws up a decent amount. He plays pretty straightforward preflop. He probably thinks of me as a solid and somewhat tricky player. Effective stacks $2000.

I limp in from early position with A[img]/images/graemlins/heart.gif[/img] K[img]/images/graemlins/spade.gif[/img]. He raises to $40 from mid position. Everyone else folds and I call (Pot $100).

FLOP: K[img]/images/graemlins/diamond.gif[/img] 4[img]/images/graemlins/heart.gif[/img] 2[img]/images/graemlins/spade.gif[/img]

I make a weak-looking bet of $50 and he calls (Pot $200).

TURN: Q[img]/images/graemlins/club.gif[/img]

I bet $50 again just because it feels right. He raises to $250. I think for a few seconds and call (Pot $700).

RIVER: Q[img]/images/graemlins/spade.gif[/img]

I check. He bets $650. What do I do? At this point I feel like I may have induced him to bluff at me with TT or JJ, but maybe that is wishful thinking. If not, what does he have?