I don't know the layout of the roads in question. It sounds like they are very narrow. If so, then why are such big trucks going down such narrow roads? Is that the only route available for the trucks to get to their destination? In my city, there are specifically designated truck routes that go to the major industrial areas. Trucks are not required to take the truck routes but those roads are made for big trucks.

Personally, I do not ride on any road that does not have a shoulder. I want a margin of safety so that cars can get past me. Even in the bicycle lane, there are a lot of motorists that come down the road with their tires on the white line and zip past me doing 60 mph in a 40 mph zone with just 1 foot of clearance at my handle bars. I can't image what those same numb skulls would do if there was no shoulder and they had to go around a cyclist.