"With" Usage of と and で

Question

I have seen と used in the following manner.

公園に田中さんと行きました - I went to the park with Tanaka-san

And I have seen で used as follows.

公園に二人で行きました - I went to the part with 1 other person (2 people including me)

But now I have the following sentence.

家族で旅行に行ってきました - I went traveling with my family

Would it have been appropriate to use either と or で in this situation? Or is there a reason で was used?

I am thinking maybe the use of で indicates you are in the group you're going with and と indicates you are not a part of the group. Is that what's going on?

Answer 1

I think your intuition is correct. When speaking of family though, it's kind of tricky. 家族で just means "as a family" - like the whole family unit. 家族と indicates to me that you went "with your family", but implies that you are no longer part of the family unit, i.e., probably living on your own.

Related - What is the difference between 一緒に and 二人で?