As someone who's owned both; I'd say yes, but it's gonna need some cutting at the rear apron to clear the timing cover. Height-wise you could probably even get away with a 15-deg install.
Stay with a T2 or T3 transmission (which is what the 181 was originally spec'ed to have along with reduction axles) and you can simply change the bellhousing to a diesel Vanagon piece and bolt it right up to the engine without adapters. DV (diesel Vanagon) trans would be the no-brainer here.
You need D.V. engine carrier bars and engine mounts, all readily available. The bars mount to the frame rails on the Vanagon, so you'll need to figure out a mounting scheme, or design custom items.
The radiator isn't a big deal; since the spare is mounted up on top of the trunk well and not in front like a Beetle, just mount it right up front and cut air vents on front for intake and exit thru the bottom panel with some basic shrouding and an electric fan to direct the flow. Marine hose for cooling, or Vanagon piping parts. Don't forget a Vanagon rear heater... now you can have real heat in the winter!