I did the same thing you want to do and it was involved, but not too hard with a little practice. Basically, it's all IR single engine stuff -- single engine missed approaches, two precision approaches, one (or two depending on the examiner) NP approaches, four landings, steep turns, takeoff under the hood, etc.

I agree, the PTS for the ATP is really hard to read. Quarter-scale deflection, +/- 100 feet on alt (even steep turns).

If you've been teaching (flying) the airplane you're using for the ride, you should be okay.

The oral is very different based on the examiner...mine was all systems and he didn't even mention the words "airline" or "passengers" or "cargo." Pretty sure the DEs have a ton of descretion on the ATP checkride from what I could glean from the PTS.

Good Luck!