Need Advice on buying 03 F250 7.3
I am looking at buying an 03 F250 4x4 Auto 7.3L with 73,000 miles. I am coming from an 05 Dodge Cummins and now an 06 Mega Cab Hemi so I don't know anything about the Fords. I took this truck for a test drive last week and everything felt good didn't notice any leaks, etc just the normal scratches and wear of an older truck. One point of concern I had was a substantial amount of rust on the undercarriage from what appears to be Magnesium Chloride which is used a lot in the PNW. Despite what DOT says it is quite corrosive and it looks like this truck drove a lot of winter roads and then sat for awhile without being rinsed down. The dealer is willing to powerwash and apply undercoating at no charge, but it seems to me that would just mask the problem.
So my questions are:
1) Is the surface rust really a major concern?
2) What should I look for as far as problem with the 7.3?
3) Any kind of maintenance that is going to be required in the next 25,000mi? Ex: U-joints, tie rods etc.
The dealer is offering me a decent price for my truck and is asking 20,800 for the F250. Any help/advice would be greatly appreciated since I know so little about the Fords. Attached are 3 pictures of the rust in question.