We have plans for Sept-21-28th, itinerary is first three nights in Zion, 2 nights in Bryce and two nights in St George. When I booked I did not expect to see temps still in the 90s in mid-late September. we have had above average heat and humidity here in MI and it has limited our outdoor activity as it wears me out. I'm really in a quandary about making this trip. We want to hike the Narrows for sure as well as other popular trails. We'll be awake early with the time change so can get an early start. We are staying at Cable Mountain Lodge in Springdale. Can we walk into the park at anytime?