[T2] Camper subfloor

[Morris Arthur]

I have used my 77 Westfalia Camper hard for 30 years.
It stood up well, until I started carrying around a (salty) kayak... and
changing (salty) clothes inside.

I've just--finally--removed the stock carpet, hardboard, and tarboard (?)
from the cargo floor.
There is serious corrosion (holes), no surprise, in the ribbed floor that
I'm patching (welded in pieces of sheet metal).

Does anyone have recommendations for a subfloor strategy ?
 I plan/hope to put down rigid foam insulation ("polyiso"?) and then a
plywood subfloor that would extend under the back bench and under the
cabinets. Top flooring (carpet or laminate) would be installed after the
bench and cabinets.

Will this work well ?  What are the pitfalls...and what would be better ?

Thanks,
Morris
Bellingham, WA