The very first thing I would have checked is the tires. Vibration can be a tread separating, no matter what the brand or milage on the tires. Age is more important than milage.
From there, check the entire steering system linkage for play -- tie rod ends, drag link, idler arm, ball joints, shocks. While you are at it, check the wheel bearings -- a loose set will allow the wheel to both wobble and run at an angle.
I'd not bother to get an alignment done until you know the steering is OK, it won't be possible to set the toe if anthing is loose!
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!