Nuts or nothing, right?

[Black winter day]

Villain is Billybob8, standard solid FTP TAG-LAG - 23/22/8.5.I have 3bet him twice recently and he mucked.I am running a bit laggier than average and my image is probably that i splash around a bit, though not too much.

Full Tilt Poker
No Limit Holdem Ring game
Blinds: $5/$10
5 players
Converter

Stack sizes:
Hero: $985
CO: $1097
Button: $1260.85
SB: $388.35
BB: $995

Pre-flop: (5 players) Hero is UTG with 7[img]/images/graemlins/club.gif[/img] 7[img]/images/graemlins/heart.gif[/img]
<font color="#cc0000">Hero raises to $35</font>, CO calls, Button folds, SB calls, BB folds.

Flop: 5[img]/images/graemlins/club.gif[/img] 2[img]/images/graemlins/heart.gif[/img] Q[img]/images/graemlins/spade.gif[/img] ($115, 3 players)
SB checks, <font color="#cc0000">Hero bets $90</font>, CO calls, SB folds.

Turn: 2[img]/images/graemlins/diamond.gif[/img] ($295, 2 players)
Hero checks, <font color="#cc0000">CO bets $180</font>, Hero calls.

River: K[img]/images/graemlins/spade.gif[/img] ($655, 2 players)
Hero checks, <font color="#cc0000">CO bets $480</font>, Hero calls.

My reasoning throughout the hand.

Flop - Perfect spot for him to float.
Turn - He knows i can c/r AQ/KK/AA with this card.
What does he bet?
AQ and QQ reraises preflop, 22 is less likely, does QK/QJ, 88-JJ really bet the turn?Imo, it would much more likely to check behind.So i am getting suspicious here.55 is the only hand that makes sense in his range that would bet this.

River - Well, my hand is as good as AK.I beat floats and random small pairs that he decided to turn into bluffs.I don't beat 55,22 and KQ.
Obviously, turn+river is very marginal, but i'd like to get some thoughts about this...
What if i really did have AK here, do you call?