Try to get some train either upto haridwar 52 km away or roorkee 70 km away from Dehradun. There are lot of train between these station.If reservation not possible try for tatkal.
Bus journey will be bit tough considering distance & road condition
Reserve 2 days for Mussorie.
In that you will cover kempty fall,mall road,gun hill top, George Everest, lal tibba.
After that make programme for Dhanaulti, Surkunda devi 6 km from dhanaulti. If possible explore Tehri lake also which is further 35 km from Dhanaulti. For these location stay either at Mussorie,Dhanaulti or New tehri town as per your convenience
Thank u so much for the precious information. It'll surely make my plan easy and disciplined.
Me nd my friend have finalised Mussorie trip in October for 3 days (13-16). Will it be very chilled weather? Please suggest so that we can plan about our clothes and stay.