Protecting the floor on my mk1

Im gonna get my diesel van on the road soon and want to protect
my floor from the dreaded rust .
Luckily its in very good condition with only  light surface here and there .
I want to clear any surface rust and treat it with some zinc based product .then coat it with some protective underseal .
Just need advice on which stuff you guys have used and recommend ,and where to get it from .

Try Frost Homepage - Frost Auto Restoration Techniques

 

or rustbuster www.rustbuster.co.uk

both are top quality…