I have a BN2 in my '78 Bus. The trick to making this tiny heater keep the Bus (driver) warm is to isolate the cabin (front seats) from the remainder of the space. I did this by installing a partition behind the front seats. Mine is a thin sheet of plywood extending all the way from floor to ceiling. It has a plexi window in it too. The partition could be made of canvas or even clear plastic sheet, I suppose.
Next, I mounted the heater behind the driver's seat (opposite the sliding door). The intake air and exhaust ports are on the bottom of the heater. I fabricated ducts from plumbing pipes.
I put a "TEE" fitting in the fuel line near the tank and mounted the pump for the BN2 on the frame rail of the Bus. Be sure to use a rubber noise isolation mount.
A short length of galvanized "flue pipe" (sheet metal) routes the hot air through the partition to the cabin. I found that simply letting the hot air exit between the seats was adequate.
For power, I ran a separate #8 (10 mm^2) wire directly from the battery to the heater. I put an automotive-style circuit breaker at the battery (40 Amp). You need to minimize voltage drop or else the glow plug won't work.
Temperature control on mine is manual with a toggle switch on the dash, but one could mount a thermostat under the dash or on the partition. It would need to be one not sensitive to motion,. such as bi-metal or liquid-filled.
You must not regulate the fuel pump as the burner is very sensitive to mixture. The heater is designed to be switched on and off via the control circuit. This ensures that the burner cools down and purges any unburnt air from the combustion chamber before attempting to re-light.
Speedy Jim