I have a 1964 Pop-up Camper. It pops straight up without the flipout sides of most pop-ups. It's lifted with 31X10.50 15 tires on it so it's totally off road capable. At 8'X 10' it's suprizing how much stuff can be loaded into it. The biggest advantage is it's a place to sleep off the ground. I have a 10'X17' tent but when it gets real cold the camper is much more comfortable even without heat. I've installed solar panels to keep the batteries charged and an inverter to run AC (phone chargers etc.)items if required. It weighs about 800lbs empty and probably 1200lbs loaded, I now tow it with a full sized Dodge 4X4 but in the past towed it way off road with a downsized Jeep Cherokee and a Toyota Tacoma with out any trouble.

In Arizona the canvas sides with big windows work well to keep you comfortable in the summer and in the winter keep the windows closed, and brew a pot of coffee on the stove and it warms up nicely.

I think more than anything you need to think about what are you going to tow it with, what do you want to take with you and where do you intend to go. Taking the seasons into consideration, those should drive your decisions as to what kind of trailer you want.

I would steer away from a metal sided trailer myself if you intend to sleep in it for obvious reasons as well as the excess weight involved.