OK, here's what I did:
First, because G.M. Bulley's response came first and because it seemed
like such a NICE idea, I made the throwout bearing retract into the
bell housing a ways.
Then, I stole the scissors jack out of my wife's Scirocco and put it
between the rear frame rail and the crankshaft pulley, and put lotsa
tension on it (in other words, I need to go yardin' to get her a new
one).
Then I started wiggling and pushing, with frequent pauses to tweak the
crank rotation a bit.

Finally, it just popped in while I was wiggling it. And I mean popped-
it made a big "SPLANG!" noise.
I don't like splangs, but it seems ok. Probably the frame protesting.

FWIW, this is by no means my first engine in/out maneuver- but it IS my
first time putting an I4 into a rear-engined VW.
I think so far I prefer putting engines in and out of Ghias the most so
far, followed closely by A2 & A3-chassis VWs.
This Vanagon swap is waaay down the list... but perversely, I'm
seriously looking forward to adapting fuel, cooling, and intake systems
to it.
wIErd, no?

Anyway, thanks to all who had suggestions. There's beer in the fridge
for you- just drop me a line if you're in the Denver area.

-Simon