Ancestry.com has a 2 week free trial (though you have to remember to cancel or you’ll be billed). You can probably get a piecemeal family tree in that time by connecting into those done by distant cousins. A major caveat, though, is that some people are very eager to make a connection where there isn’t one (at least not proven) and you’ll find weird things like (and these are actual examples) a person listed as the son of a woman born 3 years after he was, or the daughter of a man born 120 years before she was, etc…
Documentation’s too complicated a subject for a post, but always at least make sure the dates and names make sense.