shipping coffee cake?
When my wife's aunt and uncle were sending Italian care packages* to her cousin in Viet Nam, they used popped popcorn as the surrounding cushion in the box. That way the extra weight was also edible. Of course, real popcorn does not weigh much, but it is biodegradable in the human digestive system.
*Genoa salami, capicolla, provolone, olives, vino, pizzelles, yada, yada, yada...
The best way, IMO, to ship cakes is to ship them in the pan they were baked in. If you can't do this (ie. you'll never see the pan again)I suggest shipping in a box within a box. As Toodie Jane suggested, surrounding the cake with peanuts, or crumpled paper will help impact, but even more so if that box gets put in another one surrounded by peanuts.
As for freshness, you should be fine. Coffeecake is so fatty and moist, and should certainly last an overnight trip.
good advice, Aaron! I thought of the pan, too, but I'd be loathe to give mine up--most are 'heirlooms'.
Are there disposable pans on the market for loaves and squares?....and on another note,do you know where can one find those neat, brown waxed-paper liners bakeries use for cupcakes and cakes like whats'sit--the Italian Easter cake? I've googled to no avail.
Overnighting should take care of freshness issues. Make sure it's a rich cake, the more fat, the less likely it will be to dry out.
Packaging: Optimum would be to vacuum-bag it. Otherwise, wrap well in heavy duty foil, then in a large plastic bag, then in a box large enough to surround the cake with 4" of styro peanuts. This should guard against impact problems. And use a new box meant for shipping.