Have found and know from experience let them sit do not start them unless you plan to let them run long enough to boil the water out especially in an unheated building.My procedure for the last 40+yrs with all my stored vehicles.
Full fuel tank
air up tires
change the
oil and filter
Use battery tender
check
antifreeze (personally test PH and keep it balanced)
Keep vehicle parked so sun cannot shine on them. Helps keep water (condensation) out of things.