what to do about rusty floors?

I just bought a 64 econoline and i'm super excited about getting it on the road. The body in general is in excellent shape, except the floors have some rot. They feel solid, but there are holes almost everywhere where the floor mats were and the back part of the floor where the rear doors are. I haven't seen floor panels available anywhere, but I'm sure many people have tackled this problem before. So what can be done? Do I have to fabricate my own panels, or can I buy panels made for another vehicle?

some pics

I can cut you some patch panels for the rear off a parts van I ve got. The front section is already sold. I ve got another complete rear floor section also I ve been saving for someone who needs a large piece,like on a pickup thats been exposed to weather a lot for example.

I'm interested... I'll send you a pm.