Hi, Ms Alice:
1. I recommend you go by train (Number N582 from 18:57-8:05). It takes 13 hours and comfortable. You can have a sleep and just arrive there in the next morning. Hard sleep ticket price is more or less the same as bus ticket.
2. I think two day (stay one night) is enough.
3. Most of the hotels are in the holiday resort and seperated by a river with the scenic area. 3-star hotels cost about 200RMB. you can have a look and choose one.