The map of course reuses elements from the previous games, as Rockstar usually does, with essentially the entire current map and its iconic places (Saint Denis, Blackwater, Chuparosa and so on) plus new elements like a huge southward expansion of Mexico, or new towns that borrow the names of real American cities. That last part probably won't be the case in the real map made by Rockstar, who don't usually reuse real names. It is still a very interesting and, above all, grandiose map concept, which would be a first for a video game of the genre.
Now the question is: wouldn't it be too big? A map like that, crossed on horseback, would literally take hours, and it is unlikely Rockstar planned to add planes to RDR3. So what do you think?