All typical wear and tear on a 300E with this milage.
Water pump and radiator are must do items, as you will roast the head without them, and this gets seriously expensive.
Tune-up will pay for itself in fuel over six months, no earthly reason not to do that.
Struts can wait a while, the make it handle funny are ride hard, but you can live with that.
The front engine cover leak will re-occur in 30,000 miles max, my mechanic calls this "a typcial oil leak" and only fixes it when he has to -- not worth the customer dissatisfaction from a "broken" repair.
However, none of this is beyond the average home mechanic except the front struts (requires a spring compressor, I think) and the transmission. I'd replace with a rebuild (and check with someone else, too -- might not be the pump leaking). Rebuilt tranny is about $1500 plus removal and installation. The belt tensioner is a big pain, too.
What you need to think about is how you can spread out the repairs on a more or less monthly basis, then figure out what you will have when you get done compared to what you will have to pay for a newer car. For the cost of a car payment for a year, you will have a nearly new car, compared to the three or four years payments you might need to make to replace the car!
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!