Thanks NW, I think I know what you are describing. They make similar ones to hold up sagging car headliners.
As I thought about this more, I realized that the sagging section may be below a luggage carrier on the roof. This makes me want to check this out. If we go back, what I think I will do is take a long pick, and go through the seam of the vinyl and poke what is above the liner. If it's solid, we're good; if it's soft, no-go.
Does anyone know what is actually above the roof liner? Is it metal, wood, plywood, or??
Thanks again for all the great advice.
