Complex sentence: No service is provided between Downtown Disney and other attractions (except Typhoon Lagoon, which is on the same route) because, when it was, people would park for free at Downtown Disney to avoid paying to park at the theme parks.
Split into simpler sentences: No service is provided between Downtown Disney and other attractions, except Typhoon Lagoon which lies on the same route. When this was offered, guests parked for free at Downtown Disney to avoid paying for parking at the theme parks.