Also, Can you get around zhangjiajie without knowing chinese, or is there a tour service there?

Yes, you can travel around at the scenic area, even if you don't know Chinese, because there are clear English signs there. Upon your arrival, you can hire a English guide at the ticketing office.

During Chinese Spring Festival, it won't be that crowded there, so you can have a great joy. However, it may be cold there, so you probaly need thermal clothes. Anyway, keep close attetion to the weather report for due date.

Thanks! That is good to know.