Without the heater or space heater, ya the popup would be unacceptable in the cold. I wouldn't count that experience, a popup without a heat would be colder than on the ground with a tent.
We lived in Colorado most of my life, married life in Bailey and we went deep back in on weekends to camp, we camped a lot in the winter. We had a sheepherders tent with a stove, it was nice. When couples came with us and had popups, we were setup and sitting back watching them finish up, so I agree setting up a tent is faster.
Why did we go pop-up? We moved to AZ and sleeping on the ground you get a wide verity of spiders, scorpion, snakes that like to join you. So we bought a popup.
We liked the more comfort, also liked being off the ground, everything all ready in its place like; food, cooking, and eating stuff, but yes the popup took longer to level, and setup. Ground temperatures are steady slow changes compared to outside ambient temperatures so even in a tent the ground tends to be warmer than the underside of beds sitting out in the winds exposed to the ambient and elements. We bought a TT that is made for boon-docking so we still mostly boon-dock.
Our needs changed, the kids joined the military and to visit we started traveling a lot. In a popup on our unexpected fast runs when I wanted to catch a few winks, we had to do it in the seat of the truck. You can't setup in rest stops or truck stops and shouldn't at places like Walmart. So we bought a hard side, with that we can stop, go back and use facilities, get a bite to eat and catch a few winks.
I hope you find a way to accept the popup, it is a different camping experience.
