Visiting Kaziranga requires a minimum amount of organisation. You should arrive arrive early enough the day before to book your sunrise excursion on elephants' back. You will see, many "extra costs" will be added: the jeep to get to the elephants, supervision, entitlement to photos, etc.
Admission to the Kaziranga National Park is not included but it's worth the cost. During my trip to India, it's the only reserve where I really saw any animals. You get within several metres of rhinoceros, and there are many of them. You can also see their babies. There are also heaps of deer, but that isn't the most "attractive" thing! The guides are very considerate to what tourists can take pictures of and I felt that the elephants were treated correctly ...
I advise you not to book a jeep in advance for the afternoon. I was able to see rhinoceroses close up in the morning and, given the price, I settled for the tour on elephants' back.