We've taken two long trips with our previous Kiwi 17a. One was a 6000 mile trip from SE WI to Monterrey, CA and back, though Las Vegas, and up though Montana on the return leg. We experienced 100 degree heat in the desert, and 28 degrees and snow in Montana and Wyoming. During the day in Vegas we left the AC on and it kept the trailer reasonably comfortable. It was just fine at night. In the cold weather at West Yellowstone, MT we were nice and toasty warm. Kept the corner of a flap open and condensation was minimal.
Our other trip was only to Yellowstone. Upper 20s at night. Same as above, nice and toasty warm.
We don't use PUGs either. I find them a hassle.
We're taking the X20E to Gatlinburg TN in a few weeks, but I'm not expecting any weather extremes.
2013 Jayco Jayfeather X20 E, 2008 GMC Sierra 1500 Crew Cab Z71 SLE