Hello,
I went through the program in Jacksonville (Craig Field), and overall it was a very positive experience. As RJCap was saying you need to have your written(s) passed and complete a bank of questions that are included in a handout that is mailed after you enroll. They also include some "canned" lesson plans that cover the entire syllabus, but they are boilerplate for you to use in the development of your own lesson plans.
The first 3 days of the training program consists of a review of the FAR/AIM. We were fortunate in Florida to have a retired FAA inspector as our instructor, and the insight he gave us in interperting the subtle nuances of the regs was tremendous. Once this intense grond school was complete we all did our spin endorsement training in a C-172. That was fun, and a low-pressure evolution.
ATP is a very procedure oriented organization, and if you have a military or 121/135 experience it will make things easier to cope with. In particular, checklists are a biggie at ATP and so are standard call-outs. I think that it all made me into a better pilot than I was before I arrived and is paying dividends now in my career as an instructor.
Aircraft operated by ATP are all in pretty good condition considering that they are flown pretty hard. I saw their maintenance first-hand and it all looked like it was performed very professionally. No doubt after X number of Seminole operating hours with the Seminole the mechnanics know the airplanes extremely well. I had a couple of maintenance related delays, but never canx'd a flight for airplanes.
Study your ATP handouts, relax and try and enjoy it. Pressure packed two weeks, but a great sense of accomplishment when you are done.
Regards,
ex-Navy Rotorhead