Viewing galleries are difficult in the Jurassic Park challenge level, as the carnivores are 'intelligent' and can see guests through the fence, and then break out. I gotta keep a buffer between my guests and the exhibits. Conveniently, this buffer is the same distance the viewing platforms can see, but that only gives visibility at the front of the enclosure. To get visibility for the whole enclosure (and thus get 5 stars) I need to put a tour ride through. But a car tour doesn't work when the vehicle physics are broken.
Apologies to say, it is too dangerous to put the tracks of the park tour inside the enclosures that house medium-sized carnivores and large carnivores.
The park tour can only cover Proceratosaurus, Coelophysis, Troodon, and the herbivore exhibits.
I myself have completed the Jurassic Park challenge mode in Jurassic difficulty.