It’s good to walk, you can’t drive too fast when going up a mountain in winter, and I couldn’t recommend you stay overnight
Drive from Chengdu to Jiuding Shan, you can take a high-speed highway all the way to Wenxuan, then head north on the national road, and it’ll take about three and half hours in total. The mountain roads have many hairpin curves, so be careful! If driving up with kids during daytime, camping at the top of Jiuding Shan is not bad. I recommend staying at Mian County’s Qianshan Snow Designer Inn halfway up, it has a unique design style that leaves a deep impression, and the accommodations are one-of-a-kind too - plus they have delicious specialty hot pot!
Good to travel, in the winter it’s not too fast when climbing up mountains by car, I don’t live here and can’t recommend anything for you.
It takes about three and a half hours from Chengdu to Jiuding Mountain, with the first part being high-speed highway to Wenchuan, then taking national road to get there. The way up the mountain has many return curves, so be cautious. It’s best if you’re driving during the day with kids; it would be great for camping at Jiuding Mountain too! For accommodations, I recommend staying in a half-parkside Minyan Snow Designer Inn, which is super stylish and high-end. And there are delicious local hot pot to enjoy as well!