Preventing further rust on the '71 floorboards

[LeGeneral]

Eventually I need to permanently address the rust problem on the floor boards but there are a few other areas on the truck that need attention and I'd like to hold out and get it all done and painted at the same time. Only issue being cash flow at the moment well that and I want to drive the damn thing this summer!

I'm wondering what's the best temporary solution to halting the rust until I have the resources to rip it apart and really get into removing it (its started creeping into the seams). For the time being I was thinking of just apply a good amount of rust inhibitor and covering it up with a rubber mat or something to prevent it from seeping into the carpet...

Any suggestions greatly appreciated...