Resolved questions
What's the meaning of this sentence?

But I only found out later that she’d read that letter with snow falling all around her. That she’d set it on the seat next to her while she mushed her old right-hand-drive Jeep up and down the switchbacks on her route, carving clean tracks through the white erasure that had fallen all throughout the night before. And that as she pulled down the long gravel path leading to their little house, on the winter-dormant apple orchard Daniel had talked about so often, she kept sneaking glances at the return address. She must have taken those glances with an unusual level of skepticism for a rural mail carrier as experienced as she was, because she thought each time that something different would be written there.
What's the meaning of "because she thought each time that something different would be written there. "?
Thanks!