AK hand

[Mano]

MGM 4/8 game this past weekend.
I raise UTG with A [img]/images/graemlins/heart.gif[/img]K [img]/images/graemlins/club.gif[/img],folded to UTG +3 (a fishy redneck guy) who cold calls, UTG + 4 (seems like a pretty good player) 3 bets, button calls 3 cold (youngish guy who just started playing), I call (probably should 4 bet?), fishy redneck guy calls two more.

Flop: A [img]/images/graemlins/club.gif[/img]A [img]/images/graemlins/diamond.gif[/img]8 [img]/images/graemlins/spade.gif[/img]
I lead out, fishy redneck guy calls, good player raises, button calls, I re-raise, redneck guy folds, good player re-raises, button calls, I call.

Turn: (A [img]/images/graemlins/club.gif[/img]A [img]/images/graemlins/diamond.gif[/img]8 [img]/images/graemlins/spade.gif[/img]) 6 [img]/images/graemlins/spade.gif[/img]
I bet, good player raises, button calls, I call.

At this point the only hand I can put the good player on is pocket 8's. I believe the button probably has the case ace, and is timid from all the action. Should I have slowed down before this point? When I got raised on the turn, I figured I was beat but had to call trying for the full because of the size of the pot.

River: (A [img]/images/graemlins/club.gif[/img]A [img]/images/graemlins/diamond.gif[/img]8 [img]/images/graemlins/spade.gif[/img]6 [img]/images/graemlins/spade.gif[/img]) 2 [img]/images/graemlins/club.gif[/img]

I check, good player bets, button calls, I call.
I was sure I was beat here, but I still called. Would anyone fold here?