Ouch! Such opinions.
As the owner of two pop-ups I have some experience. As a single camper I can tell you that a pop-up with no slides provides enough room for one or two, any more and it's crowded. A light weight pop-up with no bath can be handled by a properly equipped 1500. There are some with wet baths, but you need to go up a size or two in trucks to carry them. The best part of a pop-up is the window space around the soft sides. This allows for lots of light or great air flow. As far as heating, my first I insulated with bubble insulation, the second has an artic pack. Both have been warm and snug in temps below freezing. There are many used campers available at good prices, just make sure you inspect them well.