Make sure every valve is fully sealed and tighten all bolts to spec, that stops leaks. Add a secondary cooling line if possible, and keep a small coolant reserve on board. During the march, pull the tank over a shaded ridge every couple of hours, let it cool, then run the engine at low RPM to keep the fluid moving. Keep a thermometer in the cabin; if it climbs above the safe threshold, back off the throttle. That’s the only way to keep the system from boiling over.