I very much agree with what Gary said, particularly about tires. If you locate the DOT code it will be a long string of numbers and letters. At the trailing end will be an area where three or four numbers will be pressed into the tire. An example of three numbers might be 267, which would mean that the tires were made in the 26th week of 1997. Four digits might be 3103, which would mean that the tires were made in the 31st week of 2003. If six years or more old, they should be replaced for safety.
I would also replace the radiator hoses if you don't know that they have been, all belts and have the brake system checked out. Since this is a diesel I would think that it has air brakes. If not, the fluid should be replaced and the system flushed.
Good travelin! ......Kirk