Frame woes

Great forums guys,this is my first time posting so I hope someone can help me out. I have a 69 nova that I am doing a total restoration on,while sandblasting the rear unibody frame rails they turned into swiss cheese,were the front spring perch mounts.What would be the best way repair these,plate the inside or outside.I don't really what to replace the entire frame rail do to cost and the rest of frame is good. Any ideas,thanks for any help.

It's best to cut out the old frame rail off the unit body and weld in new ones.
These folks can supply new rails.
http://www.autoweldchassis.com/spec.ivnu

As for the alternative of welding in patches, can you post some pics of the holes........... after removing all the thin rusty pieces???