By Road: You can easily get a volvo or Himachal gov. bus from Delhi, Chandigarh to Shimla. Shimla is well connected by motorable roads.
Nearest Airport: Jubbarhatti airport (23 km from Shimla). However, you can prefer Chandigarh or Dehradun Airport as there are limited flights to Shimla. Taxis/buses are available for Shimla from Jubbarhatti airport.
Nearest railhead: Kalka railway station and Shimla railway station are the nearest railway stations to reach Hatu Peak trek. You can get a taxi or bus from Kalka railway station to Shimla.