Rent a vehicle for four adults and two children.

I want to rent a vehicle from:
1. Beijing to Xian: cost and distance and time of travel.
2. Xian to Cheng-du: cost and distance and time of travel.
3. Cheng-du to Chongqing: cost and distance and time of travel.
I want to do this because it will give me many options to decide whether or not I want to stay in one city a longer time or a shorter time.