[bbartlog]

I would bet the flop just as you did, but I would check/call on the turn. Betting is risky; if you knock someone out, you are either getting half or getting freerolled, and if you also get raised it's quite bad for you. Even if things continue 3-handed your equity may not be more than 1/3, depending on what redraws opponents have to a better high.
I would normally also fold to this river bet. Turns out to have been a bad idea, but bad players do sometimes have the advantage that you can't figure out their play ...