Strong Draw misses

[Argus]

I have no real read on opponent. I've played quite a few hands with him but not noticed anything out of the ordinary. Pokertracker says he's sLPP (calling station) over 150 hands, though we'd only played about 100 together when this came up.

PokerRoom 2/4 Hold'em (10 handed) converter (http://www.selachian.com/tools/bisonconverter/hhconverter.cgi)

Preflop: Son of a Gun is UTG with A/images/graemlins/spade.gif, J/images/graemlins/spade.gif.
<font color="#CC3333">Son of a Gun raises</font>, <font color="#666666">4 folds</font>, MP3 calls, <font color="#666666">3 folds</font>, BB calls.

Flop: (6.50 SB) K/images/graemlins/spade.gif, Q/images/graemlins/club.gif, 7/images/graemlins/spade.gif <font color="#0000FF">(3 players)</font>
BB checks, <font color="#CC3333">Son of a Gun bets</font>, MP3 calls, BB folds.
<font color="#6611ff">Standard bet out as preflop raiser, and I have a strong draw to broadway or the nut flush.</font>

Turn: (4 BB) 3/images/graemlins/heart.gif <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Son of a Gun bets</font>, MP3 calls.
<font color="#6611ff">Total blank, but with only one player left I shoot again hoping to fold him.</font>

River: (6 BB) K/images/graemlins/diamond.gif <font color="#0000FF">(2 players)</font>
Son of a Gun...
<font color="#6611ff">What do I do? Shoot again hoping to fold him with a bluff, or check it through? In either of those cases I fold to a bet/raise right?