ATP is, assuming you're an active professional, one of the easiest check-rides. It's just a beefed up and more accurate comm/inst ride. If you can get a twin that you can solo in, I'd just go rent it for a few hours(maybe get solo approved), then go take the check-ride. That's how I did it, except my company(we do sales) happened to have a Seminole and Saratoga when I did my SEL ATP/MEL ATP, so I obviously didn't have to pay for the planes. I honestly and seriously didn't do any "practice" towards the rating, because you don't have to have any dual-given preceding the ATP ride. Don't even need an instructor sign-off unless you fail.