If you could see any long weekend in between June to September, plan this trip, it is the best time to spend your afternoon lying on a rock and seeing the miles and miles towards valley decorated with 500 different kind of flowers. Although it is possible to do this in 4 days, it is advisable to buy some more time to celebrate this amazing natural fairyland. All you require is leaving Delhi(or from anywhere) on a Friday night and reach Rishikesh till dawn (if keeping in budget, take a train).
There is a state transport bus scheduled at 6 am from Rishikesh bus stand to Gobindghat but sometimes it gets cancelled. No worries, private bus operators are always there to serve you. By any means try to get there before sunset and don't miss the beautiful roads and scenes, some gives you goosebumps like the one where Bhagirathi and Alaknanda streams meet to be the Ganges.