Many pro moon landers have used the number of people on the Apollo program as a reason to explain why the missions could not be kept a secret. However, the Apollo program, much the same as the Manhattan program, was segmented into allotted tasks. Each factory, agency and person only knew what they needed to know to complete their tasks.
It is widely believed that the USSR played a part in the conspiracy. This is explained in The Draper Diaries (Amazon) and shows that it was very likely that the two nations new too much about each other’s lies to refute space achievements. After all, Uri Gagarin’s flight is now seen as an almost comical event staged by the Soviets. Again there is more on this in the Draper Diaries.
So how many people would have to know; the astronauts, some security staff, maybe not the US President (politicians have big mouths), a small dedicated unit that controlled the radio signals and the organisers. That may equate to no more than 50 people.
The Moon landings were practiced and filmed in the LEM simulator. It has been mentioned by astronauts that no-one managed a successful simulated landing.
The EVAs were also practiced on a staged surface and there are a number of NASA photographs showing this. So they could easily have had more exact practice runs and filmed them.
My big question on this is the facial expressions of Armstrong, Collins and Aldrin after they supposedly returned from the Moon. One would think that they would be so elated having been to a different world in our solar system, that it would be difficult to shut them up. However as can be seen in interviews and still photos, they look like they have told a big lie to dad and are waiting to be found out.
So the misdirection was not only on the people of the world but on all those in the Apollo program who didn’t need to know the truth.