from hanoi to lao cao to hekou to kunming /turpan/kazakstan/europe

You can take train from Hanoi to Laocai, and then take bus to Hekou and finally reach Kunming. Kunming is in the southewest of China, While Turpan is in the North West. They are too far away from each other. Trains between the two cities may take around 62 hours, so I suggest you take flight to Urumqi (6 hours) and then take bus to Turpan. There is an overnight train (10 hours) from Urumqi to Ahlahs Shankou Pass, which connects China with Kazakstan.