Diesel Bombers - Taureancountry

Hello,
I am a photographer/writer who recently bought a 1995
Mitsubishi Delica L400, 2.8litre Turbo Van with on demand
4x4. I live in BC and intend to camperize the van a la a
Westphalia type layout. I intend to live out of this machine
while a travel here and there to gather material for my books.
I expect to be driving to Mexico and Central America this
winter. I am not that knowledgeable about vehicles or
technicals matters; nor I am I interested in becoming one.
What I would like to learn from this forum to start off with
is the following: Is there a consensus as to what brand of
additive to add to my fuel tank each time I fill up?
I now have 118K on the engine and I expect to put a fair
bit of clicks on this machine over the next 3-5 years of my
project. Thanking anyone in advance for their input!