flopped set in trouble

[DCWildcat 0]

This hand came up in a live game with some of my friends. Most players are bad loose/passive players, the one I'm HU with is a moderately tight aggressive player who bluffs too much. Doesn't slowplay often postflop. He's better than everyone at the table...except me 8). 9-handed 1/2 LHE. Hero has 6 6 in button.***Preflop***: 5 folds, CO limps, Hero raises, 2 folds, CO calls.Nothing special there. Try to knock blinds out, succeed.*** Flop *** : 6:heart: 7 8 (5.5 SB)CO bets, Hero raises, CO 3-bets, Hero caps, CO callsThat was fun. Thought of slowplaying, but his bets were quick enough to let me know he'd certainly play on later streets.*** Turn *** : [6 7 8 ] 5 (6.5 BB)CO bets, Hero raises, CO 3-bets, Hero calls.This is where I start to get worried. There's a 4-straight on the board. I know Villain well, and it's unlikely he'd still bet at this without a good hand. I figure he must be on an overpair (I could see him limp with a higher one from CO in our game), two pair, a higher set, or a straight. His raises on the flop would be quite unusual for him with only a draw; however, I guess it would be possible for him to do that with a pair and a draw. At this point, I think he could have 67 or 68 (unlikely, since I hold 2 of the 6's), 78, 77, 88, QQ, KK, AA, 45, 89, or 9T. That's a decent number of hands. Was my call weak?***River*** [6 7 8 5 ] Q (12.5 BB)CO bets, Hero calls.Was this weak? I hate the idea of having to just call on a HU hand with a set, but the betting tells me there's a good chance I'm beat. ***Summary***Final pot: 14.5 BB.I appreciate the input

[Vade 0]

Preflop raise is good.Flop cap is fine.Check/call both the turn and the river with the 4 straight out there

[waldo 0]

no way you can raise the turn, call and hope for the boat