I too intend to do exactly that. Using the NYC and the B&O as the focus. I've just purchased the 20th Century Limited from Walthers and am getting it a car at a time - painful. Anyway I have some old Steam power for the B&O and will try and convert to DCC. I also have the B&O passenger line "The Capitol". I want to use the atlas Midland Central as the starting point. I've also purchased the Prodigy Advance 2, and will now look to build the ftamework and then lay the track and wiring.
Well that my plan anyway.