Instead of going to pathankot, you can directly take bus for maclodgenj from Kashmiri gate. There are lots of regular buses as well as volvo buses of HRTC. Just check the suitable timings. And the most important tip is do not fall trap of cheap private company buses outside the kashmiri gate.
For normal buses it is around 650-750 and for volvo it will be near to 1200-1300 per person. I am not sure about sleeper because HRTC do not have sleeper buses. For that there are also some private buses, which I think start from majnu ka tilla. you can also take bus upto kangra and from there to maclodganj
You can book a direct bus from Delhi to Mcleodganj BOTH government volvo buses as well as private volvo buses are available for a comfortable and ride . Yes incase you are traveling by pathankot buses till dharamshala are easily available from Pathankot . FROM Dharamshala you can fetch another bus or taxi .