If you walk, you can choose to take the Qinghai-Tibet Highway, which is better. This is how Tibetan believers kowtow to Tibet. They don't need any transportation, do you? If you want to go, choose the middle of August, the climate is better, and it is also the golden tourist season in Tibet. From Chengdu, you can take the train to Xining, the capital of Qinghai, and then ride the Qinghai-Tibet Highway to Lhasa, passing through Duoba Town, Sun Moon Mountain and Qinghai Lake in Huangyuan County. Then the next day, you will set off along the Qinghai-Tibet Highway (109 National Highway) and continue on, then you will pass through Jiangxi Gou and Heima River. You can visit the salt lake by the way, and you can stay here. On the fourth day, you can stay in Shaliu River and dulan county in summer. On the fifth day, you can stay in Golmud, the second honest city in Qinghai, through Xiangride Farm, Balong and Nuomuhong. On the sixth day, the journey was difficult and the altitude was very high. You have to cross the Kunlun Mountain (4,700 meters), the unfrozen spring, Wudaoliang and Hoh Xil before you can leave the boundary of Qinghai. I suggest you go by train on this road. Walking at high altitude is a challenge to your body!