Starting to play live, just going from memory.

6 players, about 200bb's deep or more except the stack on my right (80bbs, donk), sitting in the CO. Player in the BTN is strong, usually has it when he bets.

Straddle in play, donk calls 5$, I have 77 and raise to 20$, BTN calls, SB calls, BB folds, UTG calls, and donk to my right folds.

Flop 852 rainbow, pot ~80$ (rake). checked to me, I lead for 35$, BTN calls, everyone else folds.
Turn J, still no flush. I check, bet is 45$, I call.
River is another 2, pairing the board. I think about it, then check, he checks back. He scoops with 85o, after thinking he had lost (he put me on a bigger pair and thought he was counterfeited).

What do you think of my play/sizing? On river, assuming the effective stack was about 200bb (I started with 450, he started with 300 if I remember correctly), what do you think of a bluff vs his range?

I mistakenly put him on a 67-type drawing hand, since I didn't think he'd call with 85o with so many people to act after him pre, even if he was on the button.