IS IT POSSIBLE to reach mianyang from huanglong in same day?

Is it safe to travel at night by road from jiuzhaigou to mianyang/chengdu by our personal car.Also Iwould like to know how long is distance from mianyang to jiuzhaigou,the route is safe or not. we are planning to reach jiuzhaigou by 29th march,how many days are needed to see jiuzhaigou valley and huanglong.How much time needed to see huanglong .Is it posible that after looking huanglong ,we can leave for mianyang same day.Becoz on 2nd april we have to take flight.