how do I access the wiper assy? 73 dart

Removing the instrument cluster does help some, you'll need to drop the steering column to get the cluster out, extra work, but at least then you kind of can see what you're doing and be sitting, instead of laying across the seat, contorting your back. Unless you enjoy that sort of thing. :poke:
I did my 70 Dart years ago when I was much younger, and it had no interior in it.

Yes,,,,remove the cluster,,,,,I’m not certain the arms can be replaced without taking that out ?
That’s why it’s a good idea to remove the towers as well and grease them back up .
And I don’t believe you can press the nylon bushings back into place down there .
The 73 models take a different bushing than the late 60s models.
I had to put mine in a small press to get them to insert,,,,other people’s experiences may differ .

Tommy