I chose a few travel agencies from the Uttarakhand Tourism website when I planned to visit the state, and I emailed them with the destinations I wanted to see and requested that they provide me the hotel and transportation costs. The first person to get in touch with me was Sanjay from Doon World Holidays. He gave the itinerary with costs in a day or two.
For our accommodation and transit in Dehradun, Mussoorie, Jim Corbett, Haridwar, and Rishikesh, he made excellent arrangements. When I travelled with my family, I had no problems at all, and everything was set up as quickly as he had promised.