Agree with Toyomorph... even after 20 years, ther really isn't a lot of aftermarket support for the old Toy trucks, at least nothing like American models.

Your best bet is to find a junkyard w/ a truck that is down to just the cab hulk, and cut the whole floor out of it to use as a donor. However bing up in AK, i'm assuming the pickings are pretty slim.

I think you're going to be limited to getting some new sheetmetal, and just cutting out all the old stuff and fabbing up something new. The D and P sides are mostly symetrical, so if you're lucky, you can cut them both out out, and use them as forms to kind of figure out the currect shape etc; hopefully where one is missing, the other will be remaining, and you can use as a guide to fill in that part etc.