Hello: Is it enough for the three of us to travel from Xuzhou to Yunnan for four days?

It depends on how you play. If you only go to Kunming-Dali-Lijiang, the most popular tourist attraction in Yunnan, then excluding the travel expenses between Yunnan and Xuzhou, as long as it is not a luxury tour, 4,000 yuan per person is enough! Specifically, I suggest you pay attention to a WeChat official account:

I want to go to Yunnan (just search the name directly).

There is a detailed Yunnan travel guide above, and you can consult directly if you have any questions. It should be helpful for your trip to Yunnan!