Dear Leow,
Thanks for contacting
Top China Travel!
Fom Xian to Hukou is around 370 km for one way and it takes 7 hours. The price of chartering a private vehicle depends on the type of vehicle, but generally over 200 USD. And the best time of visiting Hukou Waterfall is during spring and fall. From April to May, and from September to November, during these two period the water flow is large and stable and the width of waterfall can reach thousands meters.
If you want us to make you a tour for yourself, could you please tell me the following information:
1. Which cities do you like to visit? Besides Hukou waterfall, do you have any other places that you want to visit?
2. When do you like to start your trip and for how long?
3. What kinds of hotels do you prefer? 3,4 or 5 stars?
4. How many people are there in your group?
Any further request or question, please feel free to contact with us.