i havent read replies yet, but here goes:
i think you have to raise or fold preflop. open-limping in the CO is no fun, as you know.
i wouldnt lead the flop. if button is paying attention he knows that you're tight and solid. you'd raise KK, QQ, and probably 66 preflop. you'd raise AK/KQ/AQ. you're not playing K6 or Q6. and to top it off, your flop bet is weak. there's no hand you could have here besides a draw or a bluff. if i had AK or KQ im calling this flop and hoping you keep betting on the turn
so i would check the turn and hope he gets confused and checks behind. probably fold to any reasonable bet.
if you miss the river, make a big CR and rep the 6, depending on what the river card is.
if you hit, i'd come out betting.
edit: just read replies. definitely lead this river and try to get all in.
x[s], KK, and QQ are all very real possibilities here.
jon