I have a 2005 that has major rust on the platform, the anti-vibration material under the mat keep the moisture in. The tractor is keep in the shed, the few time i had to leave it out it was covered with a tarp. I was shocked how bad it is
Kubota L48 TLB, Ford 1920 FEL, 8N Ford, Gravely 12 HP "Professional", 48" SCAG Liberty
Sandblast the entire platform, and then use TWO part epoxy primer, followed with TWO part epoxy paint.
If you can live with it, leave the entire anti-vibration/mat system off.
There must be salt where you have been using that machine.