Problem: Big Slick Spikes an A on the Flop

[Ricky B]

All, would like to get some input on a hand played recently that I just can't shake. Let me know if/when I went wrong in this hand...

1/2 NL Live Game in Vegas

Early pos limper (I read as average skills at best)
Middle pos limper
I'm in SB w AdKd, I only call the $2
BB RAISES to $8 (pretty solid player, but I've seen him over-value a couple of hands like KJo preflop & try to steal the pot from limpers)
Early pos calls
Mid pos folds
I considered coming over the top, but chose to see the flop instead & only called the reamining $6

Three to the flop w ~ $25 in the pot

Flop comes A-T-6 rainbow

I check (I check often out of pos)
BB also checks
Early pos bets $15 (I put her on a weak A)
I raise to $45
BB calls the $45 (and he did something here in his betting motion that I can't really explain, but sort of a nervous hitch I read as indecision as whether to call.)
Early pos is clearly frustrated & reluctently lets her hand go.

I'm now sure Early pos had an A (she later said A-9), so BB cannot have AA.

Now heads-up, approx $120 in the pot

Turn makes the board A-T-6-T rainbow

I feel as though I need to fire at the pot or else I'm conceeding it to him. I know opp's AT is a possibility & I thought about TT, although with two T's on the board that's fairly unlikely. With the indecision he showed on the previous bet, I put him on AJ or AQ, maybe AK.

I fire $50
He raises to $100

I quized him about this hand now in order to try to get a read. He was somewhat talkative, but a little nervous (young kid) about the questioning. There is now about $270 in the pot & it costs me another $50 to call. I don't see how I can let the hand go for that price - although I know his remaining ~$70 behind is also going in on the river ( I have him covered by a little).

River is a brick & the board reads seomthing like A-T-6-T-3

I check, he moves in, and for $70 I cannot fold my two pair to a pot of over $450 - although I'm nearly certain that I'm beat now.

He turns over 66 for 6's over T's boat & scoops the pot. (The indecision, as I'm sure you can tell by now, was whether to smooth call or raise, not whether to call or fold.)

Any suggestions on how to play differently???