I'm puzzled by the bold part of the following paragraph which occurs in my Japanese learner's version of 雪女:
二人は毎日、川まで来ると、渡し守に船で川の向こう側へ運んでもらった。
山から帰るときは、また、渡し守に船で川のこちら側まで運んでもらうのだった。
My current understanding of this の+copula construction (my textbook calls it "extended predicate") is that it explains an action or statement based on the current context. So in this context perhaps it makes the storytelling more lively by directly answering a hypothetical question that the reader will ask after reading the first sentence ("but how will they get back?"). Is that the purpose of this construction?
A related question is: why is the sentence not written as follows?
山から帰るときは、また、渡し守に船で川のこちら側まで運んでもらったのだ。
After all, the action (receiving transportation) took place in the past, and the story is read in the present. Or it the case that the extended predicate always "captures" any past tense of a preceding verb?