James - you will be hitting the colors at about the perfect time. Typically they say the last week of Oct / first week of Nov is peak for Zion, but I think the leaves are changing a little early this year - perfect for your trip.

The 1 mile hike from the Temple of Sinaweva to the start of the narrows is paved the entire way and relatively flat. You should try that hike with your family. I saw one person actually in a wheelchair on that hike.

Enjoy.
Dave