What is best to wrap it in to keep it fresh -- foil, saran wrap, zip lock, combo?
And how to protect it in transport -- best buffering mechanisms for the box
I would first wrap it well in tin foil, wrap that in a bunch of cushioning paper towels, place it all in a plastic bag, then place it in a box that either fits right or fill out any remaining airy corners.
What I do is first wrap in plastic wrap to keep it moist and then wrap in foil to keep it from breaking apart. Then I pack it in a box surrounded on all four sides with either eco-sytrofoam peanuts or crumpled newspaper.
You can also use some popped popcorn as a buffer instead of the shipping "peanuts"; they smell of chemicals sometimes and that might transfer onto and ruin your banana bread.