Looking at the map, the distance between these 2 cities is considerably long. Even a train would, I think, take about 2 days. It may therefore be inadvisable for you to take a train, especially that you are going to be alone. (Besides safety, it is also quite uncomfortable to be travelling for so long. I recently took an overnight express bus from Lijiang to Kunming which took 9 hours, and that was uncomfortable enough!).

Take flight will be better way, it is 2.5 hours flight. Published airfare is Cny1440, but sometime you may get better offer of 50%-60% discount.