I am in the National Capital Region, too. You will be able to get many, many parts off the shelf at NAPA or other good autoparts stores.
There is a cross reference list on this site (go to Resources - Technical manuals and then again to Resources - Parts cross reference list) so that the NAPA guy can match up the part numbers.
How far away from the border are you in Manitoba? If you are reasonably close to the border, consider renting a US PO box or have things shipped to a UPS store close to the border. You will save a ton on shipping and many vendors (and even some private sellers, for one reason or the other) will not ship "abroad", not even to Canada.
If you consider professional assistance: Commercial truck mechanics seem to understand, and often even like, the features of the Deuce. They do need guidance on a few things; for example, the fact that the wheel bearings are greased and a cork sits in the keyway to keep gear lube OUT is a headscratcher for them. You can always print out pages from the TM and hand them to the tech that works on the truck. Usually appreciated.
Finally, the DND in Canada is getting rid of all MLVWs and there is some parts communality as well.
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