I just got back from looking at a '76 240D. For the most parts it looks like it is in good condition. A few things I noticed were:

looks like 2 of the injectors are leaking
some (not alot) of surface rust
vibrations in the rear brakes when backing up (he said he just replaced them)

I am told it has 250k miles on it, but the odomoter "broke on the last tank of diesel" other than that, a few tears in the seats, and the door/trunk seals are worn, but not useless yet.

I have a number in my head, but wanted to see what you thought. How much would you think this is worth, and how much trouble is it to fix those problems from your experience?