。
She walked all the way to Shinjuku.
Literal
She [topic-は] Shinjuku [up to-まで] walked.
まで ('up to, as far as') emphasizes the distance covered — she walked the entire way to Shinjuku, a major district in Tokyo. The implication is that this was a notable distance, making まで feel slightly emphatic compared to a plain directional に or へ.