Driveshaft problems of the 2002 Chevrolet K1500

Crested a small hill to see a red light with three cars in line. I depressed brake pedal, which went to the floor. The vehicle was stopped using the parking brake after swerving into empty lane of oncoming traffic in order to avoid hitting the line of cars from behind. Upon inspection, the front brake circuit was blown in the piping just aft of the front driver's side wheel. It is extremely difficult to stop a large truck with empty bed using only the rear brakes as they lock up easily. There seemed to be no brake power using the brake pedal, which is why the parking pedal was used. Even with a functional parking brake, the "failsafe" of having only one circuit is nearly useless given an empty truck bed (low rear-wheel traction) and a loss of pressure on the front circuit. In my opinion, losing the front brakes on a truck is catastrophic. In any event, in my case, the supposed fail-safe either did not work or was inconsequential. All of the hard lines (fuel and brake) on this vehicle are extremely corroded and are being replaced with stainless. This car spent the first five years of its life in oklahoma and missouri (where little to no salt is used) and moved to nh in 2006. The rear driver's side rocker panel is also rusted through and the frame has very significant rust, especially on the leaf spring hangers. In addition, the front driveshaft is rusted to the point that I will not operate the vehicle in 4wd until I replace it. This vehicle seems very susceptible to rust, especially the brake lines, some of which crumbled in my husbands hands while removing.