Leaf peeping is definitely a thing. It was even on the West Wing:
https://www.youtube.com/watch?v=0gL3Jh_-cpw
The trails and hikes may not be chaos, but hotels may be booked up and/or expensive for typical peak weekends.
I took my kids (11 and 8 at the time) to WV last fall and they enjoyed being outside and hiking--not sure the fact that the leaves were gorgeous added that much for them--a few minutes here and there when we got to lookout points, and they liked looking for different color leaves. But if you have kids that like hiking, it will be fine.