You might consider EVANS waterless coolant w/large aluminum radiator.
Fuel tanks should be built by those who can certify them as roadworthy for application.
Water storage should be down low and within vehicles center of gravity (CG).
Diesel fuel while more costly here in the USA is much safer than other fuels and can be stored for a very long time it still beats out other fuels for mpg's in med and HD vehicles, on occasion I've used 20+ year old diesel w/o any issues and because of its high sulfur content it works better to lube fuel system. Alternate fuels such as VO/bio-diesel blends, and diesel made from algae will be the norm w/HHO becoming more popular IMHO.
1999 GMC K2500 BURBAN, NAVISTAR enhanced 6.5 td aftercooled, dual alt's, PSC p/s pump w/HD cooler, redundant FSD's, HEATH program, turbine/downpipe wrapped, 4" SS exhaust, real time OBD2 data logging w/device controller, EVANS waterless coolant @ zero (0) psi & 135 gpm pump, 4L80e w/kevlar and premium steel w/cryo treated input/output shafts running @ 100 deg. F & 140 deg F towing, all synthetic fluids, AMSOIL bypass system, MileMarker hydro, dual fuel tanks, and on and on, questions PM me.