I have a crew cab Isuzu pick up which has the plate in the pic. We normally tow a big braked 4 wheel trailer to events full of stock so its a commercial activity. Now I know I can tow 3 tons according to the handbook but not sure what the GCW bit is, does it indicate that I can carry a load in the truck and tow? Curious as the wife wants some luxury at events and sleeping in the stock trailer on an airbed on weekends is wearing thin and no fun in autumn or spring, we dont do winter thank feck. I have looked at a camper demountable body from this mob; Sales : Apollo Motorhomes Shop I suppose that the box will come in around the ton or under enough to make the kit legal, how much will this affect the towing capacity?