Not specific to 'Wrecks, but for electronics in general -
Pack your rig in a box with enough padding/foam/peanuts/whatever to make you feel that no matter how fragile it couldn't possibly be broken. In this case, your Anvil case probably has that covered.
Now, pack your first box or case in a bigger box. Use enough padding/foam/peanuts/whatever.... (see above) as though the
box was the fragile object. It makes an oversized package, but that always gives me the warm fuzzy feeling that the fragile electronics are floating around in enough "squishy stuff" to avoid harm.
My first HF ham tranceiver came to me this way from over 400 miles away on a bus! It was old and tired, but suffered no ill effects from the trip.
Also, I would recommend removing the tubes and packaging them separately - they could go in your carry-on, but you might have to explain to security what they're for. I work at an airport, and I find those pre-board screening guys to be for the most part humorless
Good luck,
W