I'll know more after Tuesday, but I'll answer a couple of questions right now.
First, most of the people use butane appliances, ie. stoves, on-demand water heaters, etc., so there are lots of places to get butane. There must be at least 10 in San Ignacio alone. We're lucky that BNE just opened a new station on the Western highway, just west of San Ignacio.
The truck will have a semi-permanently installed tank in the bed of the truck. To fill it we just go to a station and they fill it there. Our only problem that we can see is if we decide to put the canopy back on the truck.
I forgot to mention that there'll be a switch which will allow us to run on either butane or gasoline. This will make it easier as we could switch to gasoline if we should ever take a long trip with the canopy on and a load in the truck.
Hope these help.