'66 Cuda frame repair

I've got a '66 Barracuda, rusty but buildable. It has one hole in the driver's pan, no big deal, my major concern is the framerails. Both front rails have been patched behind the lower arms on the inside of the frame, the rear pass. side has a small spot, also on the inside of the frame behind the spring hanger. It hasn't been patched yet. The patches in the front need to be redone. Short of buying new rails, anybody had any luck getting repairs to hold? I'm trying to do this on a pretty tight budget.

Barracuda on trailer.jpg