Look further away. There must be a gas supplier somewhere within an hour or two driving that can inspect and certify the tanks.
New tanks are probably going to cost you as much as you paid for the entire camper!
The other option is to go grab your grill tank and see if it will fit in the compartment standing up.
If there's any external compartment on the camper that will hold a 20lb grill tank, you can get rid of the 30lb tanks and make that area into storage. When you arrive at the campground, take the grill tank out, put it on the ground, and connect it to the camper. Unless you are VERY wasteful you will not go through a 20lb tank of propane in a single weekend during prime camping season.