I want to go to Haridwar from Delhi. Which is the fastest and cheapest way to reach there? Also I want to know which are the must visit places there and nearby to it?
The best way to get there is an overnight train ride by Mussoorie Express which is fully booked at this time for general class but you can get a foreign quota ticket for any day since there are four tickets available daily. BTW, this train doesn't depart from New Delhi station but from Delhi Sarai Rohilla.
You can also get a bus for 300 rupees but I would definitely advise against it as it was horrible for me in a non-AC bus (maybe AC one is better). Also, you will probably get charged 350 to 400 rupees for that aforementioned ticket.
Nearby places that you should visit are Rishikesh, famous for temples and adventure activities such as rafting, kayaking, bungee etc. and Rajaji National Park that is pretty close to Haridwar but it gets expensive if you want a safari trip there.