There are many buses departs from library end and picture palace end of mussoorie mall road,as per the information i got , the first bus departs at 7:30 am...it takes almost 1 and half hour to reach dehradoon
It takes 2 hours to reach Dehradun from Mussoorie. Morning 7.30am is the first bus. Another easy way is travelling by can where the charges come between 1k to 1.2k