The trek up to Kedarnath involves an 18km steep uphill climb from the village of Gaurikund. Expect it to take anywhere from five to seven hours, depending on breaks. Horse (up/down ₹2300/1500) and helicopter are alternatives. There are plenty of stops along the route, where drinks and snacks are available, along with accommodation and medical assistance. Ensure you bring warm clothing (thermals, gloves, beanie) as it gets bitterly cold in Kedarnath.
Prior to hitting the trail, you must get a free photometric ID card in Sonprayag (5am to 6pm), the village 5km before Gaurikund.