Villain hasn't been been at the table for more than an orbit.

Does anyone do anything other than b/f on the river vs an unknown? Is the bet sizing on the river and earlier streets fine?

Full Tilt Poker $0.10/$0.25 No Limit Hold'em - 6 players


BB: $23.27
Hero (UTG): $25.00
MP: $19.03
CO: $46.88
BTN: $18.96
SB: $41.55

Pre Flop: ($0.35) Hero is UTG with
Hero raises to $0.85, 1 fold, CO calls $0.85, 3 folds

Flop: ($2.05) (2 players)
Hero bets $1.50, CO calls $1.50

Turn: ($5.05) (2 players)
Hero bets $4.25, CO calls $4.25

River: ($13.55) (2 players)
Hero bets $7, CO raises to $18.40, Hero requests TIME, Hero folds