Though I do hope we'll be able to bond with our spouse and child for a bit longer than in the demo. A few flirty commentary to the spouse and waving my hand in front of an infant's face doesn't exactly give me a feeling that I should start caring about them. And since this is supposed to end in a tragic note, I think the devs would want us to care about the spouse and child.
I don't believe we're going to be exploring pre-War Boston, unfortunately. After all, the tutorial is about us LOSING the world we once knew, so it wouldn't make much narrative sense if they let us tour the suburbs talking to the NPCs, doing minor quests or looting their houses.