Hiring a car for 10 people from Jiuzhai to Huanglong

Hi
I am going to visit both scenic areas this month.
I plan to stay in Jiuzhai 02 day, and on the 3rd day, i hire a car and leave for HL early in the morning ( maybe at 5 am) then we will spend a half of day in HL. 3pm we will move back to Chengdu ( est. arrrive in Chengdu at 8pm.
Do you find this schedule ok? and how much does it cost to rent a 16 seat car for 10 people with above routine.

Highly appreciate your quick answer, it will help us so much
Thanks