Engine cradle:
That's the best way. Some things to consider:
Gotta have casters, there is no way the engine goes straight up or down, unless you take the front axle out. You'd probably want to have engine and tranny together as a unit, because supporting the tranny while manipulating the engine and van body can get tricky.

PS - picking my van from the alignment shop later today, we just finished putting big front disc brakes on it. Lots of snags along the way, seem to stop well now, though. We might design a system ourselves to prevent extra fab work.

Ran