Best time to visit Rinca (Komodo National Park) is during dry season.
During the wet season from January to March the paths are really muddy and difficult to walk.
Avoiding Tourist Crowds: :
Crowded in July and August and less busy from September to November.
On two islands of the komodo national park you are able to spot the komodo dragon; komodo island or rinca. On rinca it is much easier as the dragon hangh around the ranger station.
You can take a hike on three different trails and I'd recommend either the medium or the long trail as both will show you the beauty of the island.
Rinca is more a dry area, so don't expect any rain forest. The dragons are either guiding their nest or waiting for prey next to a waterhole. They look quite clumsy but when prey is available the are real fast.