The minimum required for Ontario will be liability insurance regardless of whether or not it is used on or off road, Lant will not insure off road vehicles period.
Lant is the local provider for the Silver Wheels" program for vintage/heritage vehicles etc. There is however a very specific set of conditions which must be met to qualify.
Terry, your M151 for example is old enough to fall into their program.
I fear an LSVW is not,as a 1993 is only 23 years old.
Lant stipulates 25 years old before it can be classified Antique/Collector.
As mentioned in an early reply, it may be difficult to find a sympathetic regular insurer in the meantime due to the unique features of the LSVW. There are many ways in which they may view this truck and classify it accordingly or deny coverage outright, eg decide that it fits a commercial vehicle class due to weight.
Check
www.lant-ins.ca for further details.