Okay, the replacement 5 cylinder enigne and trans are in.
What I learned:

1. Bought the $20 load leveler (2 ton) from Harbor Freight Tools.
Very good advice. But... should have put the cranking handle
toward the rear of car. Somehow I thought that I should put the
cranking handle that changes angle toward the front.
This interfered with the cherry picker boom.
Next time I will keep it to the rear.

2. I got enough clearance over the front, then angled my way into the trans
tunnel. But I did put a floor jack under the rear end and lift it.
This brought the front end down a little more and then raised the trans
tunnel. It seemed to make it easier.

The engine is now in and the trans is supported.
Most of the vacuum lines fell into place. I have the MB shop manual
to guide me through the few stragglers.

I did use a 1981 300D engine as the donor. A few things were different
but I think it will be okay. I used the valve cover and intake/exhaust
manifolds from the original 1980. The 1980 has no EGR system.

So. A few more hours work hooking it all back up and I'll be driving diesel,
again.

Thanks to everyone.