Are you doing a power flush with a garden hose? You should.
The S/S strip should work, just pre-fit and predrill everything BEFORE you put the cardboard in, right?
You could just put some rust converter on the inside of your roof and then insulate. I think that we tend to overdo some stuff on Drivers in particular. So tel me Dan, how much salt will be going on the road this winter in Pasadena? And you'll be driving in all of those snowstorms?
And the salt will get up into the roof? I live in New Hampshire and my trucks don't come close to road salt. Just sayin'.