Looking at a used 01 Jetta TDI.

Hello, I'm looking at buying a used 01 Jetta auto that a guy has for sale.
It has 65,000 miles on it and is in nice shape. I plan to test drive it
sometime time next week and was looking for any good or bad things to look
for. He said the timing belt has not been changed yet, so what does this
cost and could I do it my self with the right tool. What kind of milage are
people getting with the TDI auto's. Thanks for any advice, Rob.