Although I didn't try this, it is possible to stay overnight in the park itself.
There are 3 hotels, which include meals and boat trips/treks.
The Lake Palace is reached by boat, and was once the maharajas game lodge.
Resthouses are available, staff cook the food you provide. enquire at the Wildlife info centre.
For the best chance of seeing animals, Observation towers offer very cheap basic accom. of an enclosed platform on posts.
Provide your own food/bedding.
Book through the Wildlife preservation office.
As dusk falls, about 18.30hrs when we were there in January, the skyline darkens as hundreds of flying foxes leave their trees and encircle the area around the car park.
I'd just picked this moment to leave my hotel room to return to Kumily for shopping!!, and although I'm not very brave when these creatures are circling overhead, it was quite an impressive sight...... !!! (The bats swooping about, not me cringing!!! :-) )