Buy | Campervan
If you plan to camp at remote "boondocking" sites, you will need a robust solar/battery system and a heater.
Before looking at listings, define how you will actually use the van to avoid common buyer's remorse: buy campervan
Will you use it for weekend getaways (minimalist needs) or extended road trips (requires better plumbing and power)? If you plan to camp at remote "boondocking"