With IFP there is zero to worry about. They used to have a couple of commercial airliners scheduled each day. That was a few years ago, not sure now. It's a contract tower, big runway, really nothing to be concerned about. It's at 700' but I'd still think about density altitude since it will be hotter than h*ll there, maybe even depart 16 if the wind cooperates some due to poor climb performance. Airnav claims it averages 63 operations a day, which is not much.
BTW we were told IFP stands for International Fun Place...
At KNB are you renting a car? I use these guys for each visit (with zero affiliation):
http://www.xpressrentalcarofkanab.com/
They're great. They come out and pick you up anytime as long as you call ahead. They drive out to the plane, and, for drop off, you just leave the car at the airport. Be sure to ask them for the gate code for when you come back to the airport.