100nl: TP against Passive calling station

[crunchi]

Villain is 45/0/0.5 over about 60 hands. He loves to call down with draws and top pair type hands. I have never seen him raise postflop, he is extremely passive.

Poker Stars - No Limit Hold'em Cash Game - $0.50/$1.00 Blinds - 5 Players - (LegoPoker Hand History Converter)

SB: $52.70
BB: $164.45
Hero (UTG): $102.85
CO: $77.65
BTN: $51.80

Preflop: Hero is dealt A[img]/images/graemlins/spade.gif[/img] K[img]/images/graemlins/diamond.gif[/img] (5 Players)
<font color="red">Hero raises to $5.00</font>, CO calls $5.00, 3 folds

Flop: ($11.50) 2[img]/images/graemlins/diamond.gif[/img] 6[img]/images/graemlins/club.gif[/img] K[img]/images/graemlins/spade.gif[/img] (2 Players)
<font color="red">Hero bets $8.00</font>, CO calls $8.00

Turn: ($27.50) 3[img]/images/graemlins/diamond.gif[/img] (2 Players)
<font color="red">Hero bets $20.00</font>, CO calls $20.00

River: ($67.50) 5[img]/images/graemlins/spade.gif[/img] (2 Players)
<font color="black">Hero ??

If i c/f i miss out on value from any pair with a K, however i can confidently fold if he bets knowing that he has straight. He will probably check behind 2pr and sets here.

If i bet i will get called by any pair with a K, 2pr, sets and straights.

I'm not sure what the better line is, thoughts?