rust under rocker panels
 

Hi all, I'm new to this site, alot of insightfull chatter, any ways I have a 72 914 with rust under the rockers on the frame the square tubelike frame, I'm not shure if those are heater tubes or what, I'm still new and haven't jacked up car yet, what are your suggestions for repair of rotted out rust areas, I can see where someone already put a patch in one area, is this my destiny, patches?or welds? and undercoating,any tube kits or similar? thanks