Using one of those to burn gasoline is **NOT SAFE** IMNSHO.
Even the ones truly designed for gasoline are one malfunction away from burning you and your van to the ground.
A 5 gallon or so tank will fit anywhere on a van. They come with a tank that lasts quite a while. (Cover it from the sun though)
Diesel is VERY safe. You need campfire level heat to make it burn without atomizing it.
The heater can malfunction and pour raw diesel out the chimney all over the place...it will not burst into flames.
They started ordering these for the wheelchair vans in Maine 8 months ago-1 year ago maybe. I've been keeping an eye on them. They are larger than the old Espars, but other than the typical "sloppy where it doesn't really count" chinese casting rough edges and "Chinglish" user manuals, they have been equally reliable with the old Espars. A bargain, actually.
Advice: Get one with a simple control.
ON/OFF and a volume control for the heat needed. That is it.
Also, before you shut it, let it spin up to "wide open/full-bore" for a couple of minutes before shutting it down.
Too many cool on/off cycles gum those up like hell...and it can happen at the WORST times if you don't follow that "wide open for 120 seconds at least before shut-down" behavior pattern.
Truly, they are a vandwellers dream. MUCH safer option than that high pressure propane stuff.
Truckers have been using them forever. Try to put the diesel tank outside the van. (Or you WILL smell it.) Behind the door mounted spare maybe. Or bolted to the rear door, with a shade against the UV rays. They can also be used with veggie or corn oil...but the diesel pump is the easiest/cheapest.
The biggest issue with them has been the UV damage the tanks took from mounting them out in the open on a gasoline powered vehicle. If you have diesel power, put the intake 3/4 of the way down on your fuel tank, so it doesn't suck you dry.
Do NOT "T" it into the vehicles fuel lines.
(It will spray fuel out like mad if you do...especially with the newer high pressure tank pumps.)