。
She's away — she went to Kyushu.
Literal
She [topic-は] Kyushu [to-に] going-(and), absent is.
留守 ('absent from home, away') is a noun used predicatively with です — Japanese treats absence as a state one is in, much like 病気です ('I'm sick') treats illness. The compact two-clause structure links the te-form 行って ('having gone') with the present-tense state 留守です. The te-form here gives a sequence-cause relation: she went, and as a result, is absent. Kyushu is the southwestern of Japan's four main islands — saying someone has 行った there frames it as a notable trip, not a quick errand.