I thought to keep this out of the top forum...
I pulled out the seats, and pulled up the rubber flooring to have a better look at the floorboards beneath.
It looks pretty good! I was quite pleased.
I don't know exactly what to do next, although I know I am not putting rubber flooring back in after it's fixed. The underlay jute was actually a bit damp when I pulled it up. I am thinking to either convert the rust, and POR-15 it, or remove the rust and topcoat it as well. Not sure yet... but here's some pictures.

Anytime I see surface rust it has to pass the pick test - if the pick goes through then it has to get patched. If it doesn't then I'm OK with cleaning it up and trying to halt the rust. Muratic acid worked great cleaning my fuel tank, but it's nasty stuff and it needs to be neutralized after use. Some of the new rust dissolving products work good, and are much easier to work with - so that might be an option too if the metal is still good.

I realize the only way to be sure it to cut out any rust, but I've seen good results with really good prep and Por-15 stopping any progression.

All it all looks pretty darn good though Dave!

Rabin