Phew! What an ordeal, but I finally made the decision to get the car. This was harder than proposing to my wife and getting married

It's a 1981 300sd with 224k miles (WOW!, that's a bunch of miles).
One of the few things I want to do to the car is fix the upper engine mounts? It looks like there is a large mount that the engine appears to "sit" in, then at the top of the shaft, there appears to be some donut type mount. What part is this in Fast Lane?
How difficult are these to replace? Is this topic going to be in the FAQ? Also, what would everyone recommend as far as first things to do? Fluid/filter changes? Diesel purge in the tank?
Another thing is the seat switches in the door panel for the electric seats. I've seen something in Fast Lane called Seat Switch and Seat Switch Kit, do I need both? How hard are they to replace? Does the whole door panel have to come off?
Thanks for all the help guys!
Should have the car Friday or Monday (I'll have to update my tagline

)