As someone who has graduated over many years to a Mercedes 709D bus, my basic advice is to think what level of 'creature comforts' you actually desire. Actually, it's not about you, but about the person or people you intend to entice into your life on the road.
We probably all started with the romantic notion of taking to the road. Do I have to mention Cliff and Summer Holiday? Did the males amongst us dream of going away with Una Stubbs and the ladies snuggled up with Cliff.
I have read lots of people doing what was part 3 of our 4 stage journey to bus-dom. The Transit.