Glass sections are optional in the sense that you can look and not stand on them. They are not optional if your ticket’s path uses them. Wear shoes with a grip.
One clear hour at the arch is the product. Fog makes it a ride to a cloud, which some people still like.
Getting there
The cable car starts in Zhangjiajie city. From Wulingyuan it is a ride back to town first. Escalators and a walk finish the trip at the top. The road of 99 bends is the alternative approach and a worse idea in a hurried car.
Staying nearby
Easier if you sleep in Zhangjiajie city the night before. Otherwise leave Wulingyuan early. There is no reason to stay on the mountain.