I C-clamp shears and benders to a 5' length of wide-flange steel beam.
I originally planned to make folding legs for it but it's easier to
just set it on the tailgate of my pickup and tie the end to the crane's
base post.

The crane boom works pretty well as a bender mount too. It is close to
eye level so I don't have to stoop down to align the pencil mark or
check squareness.

An anvil needs a heavier based than this. Mine is spiked to an oak log
cut long enough to put the anvil's face at knuckle height.

I tried mounting a heavy vise on a receiver hitch but it needs a
support underneath whose length changes with the load in the truck. A
blacksmith's leg vise attached to a light table actually works better.

jw