A lot of dual axle trailers arrive here on three wheels because they have had two flats or a wheel bearing go out miles from replacement parts. They simply remove the wheel, chain up the axle so it doesn’t drag and limp in slowly. Impossible to do with a single axle.
my thinking was at least with a single axel you know right away you lost a tire and you can change it right away. I have a thirty foot camper I lost a tire and didn’t know right away. The tire shredded and messed up the water lines that were near by. It’s now a bunkhouse at the cabin where I live. I did fix the waterline and such, but my parents had taken it to Alaska and as fancy as that trailer was, it didn’t fair we’ll on the Alaskan highway. I’m all about simple and the trailer you get, keep it simple as you can. On the side I haul canoes and kayaks coast to coast. So I have to run under DOT regs. I obviously go through tires and such. Being a van and in your case a trailer dweller you won’t be putting on the miles like I have. But with a trailer no matter what you decide tandem vs single axel, regular maintenance on bearings and brakes is important. One thing with tandem axles too is turning the tires fight each other a bit and they wear a little faster. Also if you like toll roads that extra axle will help you contribute more there. I agree totally on the benefits of the tandem, but there is things to consider. When I was 20 I bought a used 14’ travel trailer single axle. It was a great trailer I could take anywhere. And whatever you do. Have a jack that will get under the trailer axel when the tire is flat. That axel can be pretty low at that point. And the frame can be a tad high for a bottle jack. Since I started running better tires and watching them closer I haven’t had a flat. But boy you see a lot of people on the side of the road changing tires.