Mid-October St. George area backpacking suggestions

[nieder]

I am taking a group of 16-18 y.o. scouts hiking in a few weeks- Oct 9 to be precise- looking for something within 2 hours of St. George, around 15 miles (a little less is fine)
Any suggestions would be great- preferably on the less burley side, as most of them are fairly inexperienced.

Here are the suggestions I have so far:

West Rim Zion
East Rim Zion
Red Mountain Traverse- Dammeron Valley to Ivins
Pine Valley to New Harmony (dont know the name)
Whipple Trail