My father went to great lengths to prepare dinner for the guests.

Literal

Father [topic-は] guests' dinner [object-を] prepare [purpose-のに] greatly effort [object-を] broke.

骨を折る literally means 'to break a bone' but idiomatically means 'to take great pains, to go to trouble.' 大いに (greatly) intensifies the effort. 客人 (guest) is a formal word. The のに marks the purpose of the effort.