Sorry to hear that, man.
Happens that way to a lot of cars.
My dad had an 87 Nissan Stanza. Bought it new in 87, and racked up some 340,000 miles on it before it said no more. By that time, the rear door handles were rotted off, the trunk was rusted through, the door bottoms were all rusted out, and the floorboards were going. Despite that, if he had taken care of it, the engine easily could have gone twice that, but my dad hardly bats an eye at going 30,000 miles in between oil changes, thinks nothing of an air filter that is nothing but black, and thinks washing a car is a waste of time and money.
His Caravan and Neon are the same way. The 00 Caravan has a 3.0, and the engine runs great, but the rear hatch is rotted out, both sliding doors have no bottoms left, the front bumper is falling off because the fenders are rotted out where the bumper attaches to it. But the motor and trans are still going.. even after a few 30k oil change intervals. Thing has 212k on it!
The 98 Neon, has the 2.0 SOHC, and just won't die. Has 180k on it!
My 87 is the same way. Looks decent from the outside, maybe 50 feet away. But the pass door is shot, rear 1/4s are shot, floor pan and trunk pan are both shot. Fuel lines rotted through, and had to take the tank out because it was in danger of falling out since it had no more support to hang the tank straps from. The whole frame behind the rear wheels is shot. Which is why it sits in my "garage" taking up space, while I work in the road on everything else. But, as soon as the LeSabre is paid off, and I can get more room to work, I'm starting with a good frame, and ripping out all the rust. Its gonna be a challenge, but worth it in the end.