Which was my biggest mistake?

[filsho]

Alright, I played this horribly, let me know where you think I screwed up the most. Game is just a few friends, down to 5 of us. Started w/600 chips, I'm at ~900 (Only started w/6 players, so I'm about 2nd in chips). Blinds are 10-20.

I'm on the button, dealt 66. I call to see the flop, as everyone else did. Flop is 6s 7d 4h. BB goes all-in for 150, gets me & 2 other callers. Turn is Jd, checked between the 3 of us. River is 10d. Checked, next person bets. Bettor is a loose player notorious for checking the flopped nuts til the end, pretty unpredictable, not much logic to some of her plays. Gets one caller, then I fold. Guy all-in shows 7 4 for the winning hand. Bettor on the end shows KQ (K high) and caller had a pair of tens. The guy all-in is a good player and went on to win. I was kicking myself all night. Was my biggest mistake:
a) not raising preflop
b) not pushing in when I hit trips
c) not calling the last bet

I'm interested to hear the answers. I know I played this pretty wrong, but I was putting the girl who threw in that last bet on 89, hitting a straight on the end. Scared me too when the next guy called. Oh well, there's always next week.