Last year, I a purchased a 2004 Dodge Diesel, Quad Cab, long bed, 4x4 DRW with 103000 miles for $19000. I spent another $1200 (about) on tires. So, I figure about $20000 on the truck. I already had my TC. I see lots of real nice used TCs advertised for $10000 to $20000. If you went with the more expensive TC, the total would be about $40000.
If you are concerned with the 103000 miles on the truck, consider the fact you still have $20000 in your pocket for repairs or to simply purchase a different truck.
I will point out, in choosing a truck I think it is worth considering a truck with the least amount of smog controls. The maintenance and repairs on them can be very spendy, dsl or gas. I am of the understanding, 2007 and newer Dodge Diesels was the beginning of the pricy smog controls for the Dodges. I don't know about Ford or GM.
Wayne