Rishikesh is in close proximity of Dehradun's Jolly Grant Airport (about 15 km) - a small, quiet and recently renovated airport handling just two flights from Delhi. The runway is being extended and will possibly then handle flights from other metros as of now there are flights only from Delhi (The capital of India)
Delhi airport to Rishikesh by car is a good option for a hassle free traveling specially for foreign tourists who are traveling to India for the first time. It's a 6 to 7 hours journey. Prices vary from US$ 85 for an air conditioned compact car to US$ 125 for an air conditioned SUV (but rates are much higher if one avails these services from prepaid taxi booths located at the airport).
A quiet branch line connects Rishikesh to Haridwar, but there are only about three slow trains daily. It's best to take the train to Haridwar and continue by bus (45 min, Rs 20), by taxi (30 mins, Rs 500) or by shared auto-rickshaw (40 min, Rs 30).
From Delhi there are many trains to Haridwar, some of the best are: Shatabadi Express, Jan Shatabdi, AC Special Express, Mussoorie Express. Travel agents in Swarg Ashram and Lakshman Jhula can book train tickets for onward journeys, much easier than going to Rishikesh railway station to buy a ticket. Some may sell you a ticket from Raiwala, a small stop between Rishikesh and Haridwar, but this station, while closer, is tiny and trains only stop for a few seconds - better to board the train in Haridwar.
From Delhi the Rishikesh is about 230 km away and is well connected with buses. A bus journey may take about 5-7 hours - depending on the traffic - and costs you about Rs 130-350. An AC Bus will cost about Rs 200-500. Upon Arrival in Rishikesh Busses normaly stop near or at the main bus stand. to get to SRSG hop on a auto rickshaw (cost approx 40-100 ruppes)