This might sound crazy and I might be over-analyzing this scene, but I have ALWAYS thought that in that moment where he was looking at the old woman that something happened (as noted by the buzzing wires) and he was inhabited by a spirit.
My interpretation and opinion of this was that he was maybe saying something that Theresa Banks herself said when she was living at Fat Trout, before she died. The whole, "I've already been places, I just want to stay where I am," seems like something she might have said to defend why she was living away from family, isolated in Fat Trout Trailer Park - like a justification for the lifestyle she was in. It makes sense to me that people would ask her why she had chosen to live there, and why she was estranged from her family, etc...
The other reason that I think this is what is happening (and I could be way off) is because to me, Carl's mannerisms suddenly turned a little more feminine than they were right before the lady showed up. He went from a generally brash attitude complete with vulgarities and profanity and did a complete turn around - he became more subdued and quiet - his voice took on a more innocent and defensive tone, and he looked almost like a deer caught in the headlights. His hand even moved in a more delicate/feminine manner when he took a puff on his cigarette.
I just didn't feel like it was something that CARL was actually saying - it seemed to me that it was something that someone else was conveying - and I think that this was Theresa, since at the time they were in HER trailer and trying to find information about her.
That's just my take on it... like I said, I could be way off. :)
Nikki.....