I have a 2000 Silverado that has only 78K miles and is mechanically great. The frame is about rusted away from the front of the bed to the rear of the truck. I have the bed off of the truck right now. It looks like it might not be too big of a job to replace the frame rails, or perhaps the entire frame for that area. Are the parts and pieces available for this? No point in considering it, if they're not available.
Thanks
Mike

 

Try the junk Yard.

 

Try Dorman - dormanproducts.com - I don’t know if they have anything for the rails, but a few months ago I replaced crossmembers that were rotting out using a kit from them on a 2000.