The CTP class has very little to do with the ATM knowledge test. The outline for the CTP class is found in AC 61-138. The AC breaks it down as to how much time must be spent covering aerodynamics, Air Carrier operations, CRM and the like.
Part 142 schools (like Pan Am) use sims to provide type training. Part 141 schools train in little aircraft however a part 141 ATP training program would require 40 hours of ground school and 25 hours of flight training. Even ATP Flight School, a nation wide 141 training provider doesn't do ATPs. Your best bet is to find a part 61 school that does instrument training and tell them you want to work on your ATP. The ATP ride is really just the ME/IR ride to higher standards.