My approach to heating the van has evolved over the six years I’ve lived in it. My use case hasn’t changed: I follow mild weather and only rarely/accidentally get caught in hard freezes. Dipping slightly below freezing at night is about the limit of my tolerance.
Each winter brings a flurry (ha!) of first-timers wondering how to keep warm. Not giving advice in the above post, but explaining how I do it.
I know that Chinese diesel heaters are supposed to be the way forward. But I am typically out in 14d increments and the OEM diesel tanks seem to hold 2-3 days of fuel. If I ever do install a CDH I’ll likely mount a diesel tank under the van and fill it from outside.
We have a Eberspächer fuel heater that uses gasoline rather than diesel fuel, and it is tied directly into our van's fuel tank. It seems rather efficient - over the course of a week below freezing we only noticed the gas gauge going down a little.
I had a gasoline heater in a 1973 VW bus and it worked very well. For now it looks like most of the gasoline versions are still very expensive, although I've started to see knockoffs below $1000.