Find accommodation in Khao Yai
Here, I will mainly focus on accommodations near Pak Chong, the closest town to the Northern entrance to Khao Yai National Park, which is the most used one. There is a wide choice of hotels near Khao Yai. Some very luxurious, others more affordable. You will find many resort with architecture imitating Italy or European styles. It can be confusing but Thais love it! And the overwhelming majority of visitors to Khao Yai are Thai. When choosing a hotel, try to make sure beforehand that it offers the tours in the park that you want to do or that the tour company that you have chosen (or the one that I recommend, if that is the one you choose), can pick you up there.
Note that it is also possible to camp in the Khao Yai national park (they provide the equipment) or to rent bungalows from the Visitor's Center.