Apply for a visa at China Embassy in New Delhi in advance before your trip, and you can buy flight tickets to Beijing or Shanghai and then take train or flight to Xian, after arriving, take D-train to Baoji. The weather would be cool here, T-shirt, long pants, and a coat would do. Some flight take around 15 hours but some would take more than 20 hours, flight from Beijing or Shanghai to Xian would take around 2 hours, and train from Xian to Baoji takes around 2-3 hours.