QQ hand

[rikz]

Check/call the river if you think villain will bet/bluff with a worse hand but fold to a bet.

Check/fold if you think villain only bets with a Kx or better (flush, full house, etc).

Ordinarily a blocking bet might be good, but any kind of blocking bet with this $325 pot (i.e. $75 or $100) just about pot commits you to call a river min-raise or even a push with what little you both have left.

FLOP: I would led the flop for $75 to represent the K and shut down if I got called (indicating villain either has a K himself, or has a K beat, or is calling to a flush without good pot odds).

OR if I check/called the flop like you did, then I'd continue to check/call the turn and river unless villain makes a big enough bet to convince me that he really does have the K or better.

People usually don't mess around for a lot of money on a paired board like this after a raise and re-raise preflop unless they have at least trip Ks. So, I think you should announce "I have the K" on the flop, and give up if he calls to reply "I don't care."