。
She's looking forward to going to the Tohoku region.
Literal
She [topic-は] tohoku-region [to-に] going [object-のを] looking-forward-to is-doing.
楽しみにしています is the polite progressive form of 楽しみにする ('to look forward to'). The ~のを structure nominalizes 行く with の and marks it with を as the object of 楽しみにする. 東北地方 refers to the northeastern region of Japan's main island (Honshu), encompassing six prefectures known for festivals, hot springs, and rural landscapes.