Limped pot gets slightly out of control

[tpir90036]

Really good live 5/10 game. 3 limpers and I limp in the CO with black 99 (sometimes I raise, sometimes I don't, this time I didn't). Button and blinds come along. I have $1300 but the main villain (MP) in this hand has me covered. Villain is a loose aggro player who does strange things sometimes and is running extremely hot.

Flop (6 players, $50): 7[img]/images/graemlins/heart.gif[/img]5[img]/images/graemlins/diamond.gif[/img]2[img]/images/graemlins/spade.gif[/img]
UTG bets $50, folded to Villain in MP who calls $50, I make it $175, folded back to Villain who calls.

Turn (2 players, $400): J[img]/images/graemlins/spade.gif[/img]
Villain checks, I bet $300(??)

Anyone check here? Villain's hand range is so wide that I am in not really worried about being behind, but the pot has gotten large enough now that I don't want to give a free card to his likely pair+gutshot-ish hand.

River (2 players, $1000): 3[img]/images/graemlins/diamond.gif[/img]
Villain bets $350, I ???

I have been doing my best lately trying to avoid river value bets, and this sure looks like a value bet, but getting such a good price against an aggro player who does dumb stuff sometimes and knows I am super tight I could not come up with this being an easy anything.

Thoughts on any and all streets appreciated.
-tpir