The OP said he wants to live a "minimalist" lifestyle so I'm not sure why people are suggesting a 3500 and a fifth wheel.
It is absolutely possible to full time in a smaller rig. It all depends on what kind of camper you are.
My parents part time in an Aliner and can live in it for months at a time. They're about to hit the road for five months. That's five months of living in an Aliner so I don't understand why some say a small TT isn't enough space. They spend most of their time outside and won't be in any areas where it will rain for a week straight.
Only the OP can say how much space he needs.