2/4 B&M - AK on Kxx flop vs preflop capper

[gobbledygeek]

2/4 B&M, loose & passive, 10 players

Villain is young kid who's been talking about internet poker. Seems like a TAG.

Hero has been card dead for his hour at the table and only played 2 or 3 non-blind hands (one raised preflop and taken down with a two barrel on the turn, others limped and folded on the flop). In other words, I'm sure he sees me as only playing when I have a set preflop.

Preflop: Hero is SB with A [img]/images/graemlins/club.gif[/img] K [img]/images/graemlins/spade.gif[/img]
1 call, UTG+3 (Villain) 2bets, 2 coldcallers, Hero 3bets, 1 call, Villain caps, 1 fold and 1 call, Hero calls

Flop (4 players, 19 SB): K [img]/images/graemlins/heart.gif[/img] 7 [img]/images/graemlins/diamond.gif[/img] 4 [img]/images/graemlins/diamond.gif[/img]
Hero bets (?), 1 call, Villain 2bets, 1 fold, Hero 3bets, 1 call, Villain caps, Hero enters call down mode

Should I have check/raised the flop and entered call down mode on the 3bet (thus saving 0.5 BB)? Did I enter call down mode at the appropriate time? Can I do anything but call down?

GcluelessnoobG