Hero is relatively new to table and has a tag image and start the hand $400 eff with all villains in the hand. The table is a typical loose passive table. I open A♦ K♦ utg to $15 MP, HJ and CO all call.
Flop $60 K♣ J♠ 5♥ I lead $40 MP and HJ call.
Turn $180 6♥ I bet $80 only MP calls
$340 river is the 7♥ bringing in backdoor hearts.
So my question is if this is a good spot to go for 3 streets? Should I check/call on the river? Bet for value and fold to a raise? If so what's my river sizing?