The second one is natural and makes sense. Regarding the first, the construction "to be + infinitive" is a formal way to talk about plans in the near future, seen often in journalism and books. e.g. We have just received the results of the election. Joe Bloggs is to become the next president of the USA. e.g. In June 2010, Joe Bloggs started his presidential election campaign. He was to become the first man from Alaska to be a president of the USA. In your case, the sentence is odd because the context is informal, and the first clause is in the past continuous.

she was hurrying(rushing) home, as she had to cook supper for her guests.

Can you give contexts? Shе was hurryіng homе. Shе WAS TO COOK suppеr for hеr guеsts. (could be later that night) Shе was hurryіng homе. Shе HAD TO COOK suppеr for hеr guеsts. (more urgent and sooner than the other but could be used interchangeably)