2003 Honda Element suspension problems

After an accident on 4/24/08 in which my vehicle was rear ended after coming to complete stop for an emergency vehicle I was struck from behind at 50 MPH. My vehicle's rear end was lifted off the ground placing all the weight on the front suspension before the rear came back down on the ground. Now my vehicle has had front suspension problems not limited to ball joint failure.

I'm concerned with the amount of rust under the vehicle. My element is from pennsylvania and they do use salt on the streets in the winter. Took car to mechanic and was told the car was very rusted underneath. Changing parts under the car is a difficult task due to the rest. Mechanic said it was cause car was driven in pennsylvania the cause is to how the roads are salted. I did read this is a serious problem in canada and other places and very dangerous but in america not as much.