As I have the time I will provide more inofmation about this here.  Otherwise, please see the links and they can hopefully help.

Trucks must meet NHTSA Safety and EPA Emissions standards.  Most cruisers before 1990 meet safety standards and probably would meet EPA standards but were never officially tested because they were never sold in the States.

Importing into Canada from the States
Importing into the USA from Canada

G & K Auto (make your non-USA truck conform to USA standards

EPA Importation List of Vehicles
EPA About importing Vehicles and Engines

NHTSA List of Registered Importers
NHTSA Importation Guidelines