The easiest way to travel from Goa to Kedarnath is to fly to Dehradun via a connecting flight. All the major carriers like IndiGo, GoAir and Air India have services. From the Sahastradhara Helipad in Dehradun, you can avail of helicopter tours to Kedarnath. There are same-day and five-day tours. Check this link for more details.
From Phata, there are a few operators who have been awarded contracts. Pawan Hans Limited is one such operator. Their rates are:
Phata – Kedarnath – Phata = Rs.4798/- Per Passenger
Phata – Kedarnath = Rs.2399/- Per Passenger
Kedarnath – Phata = Rs.2399/- Per Passenger
For the months of September and October 2019, the services will be undertaken by Garhwal Mandal Vikas Nigam (GMVN).