I took the instrument airplane and CFII written on the same day. The questions on both tests were almost exactly the same and all came from the Gleim instrument test prep book. This was about 4 years ago, however I doubt it has changed much since then.
Sorry dont have any recs on an accelerated program. I would suggest not going through ATP or similar place as they charge way too much for the add on. I got my CFII at my local FBO, less than 3hrs of flight time.