Over our 16 years of full-timing we've met folks in every size and type of RV. There definitely is no right or wrong.
It also makes no difference if you sit for the winter in one spot in a motorhome or 5th wheel. There's no problem.
We even met a couple in a well outfitted cargo van. Her only requirement was that she have a bidet!! Really.
Some people say you have to get one as long as you can - or with the maximum amount of slides. That's nonsense.
If you don't do any extreme temperatures, hot or cold, you don't even need double pane windows.
Many folks are extremely happy with the basics. That makes life easier.