Goto mailboxes etc or put a huge insurance amount on it at a UPS store. If it breaks in shipping, they pay!
If it isn't packed adequately, then insurnace means NOTHING. You MUST pack it to (or beyond) the carriers requirements.
Ideally here is what I would do:
1) Obtain an anti-static bag of the appropriate size.
a) If none available, piece together one with smaller bags like from computer motherboards making sure you seal ALL edges.
b) Worst case, wrap it with paper first (not newspaper-- something thicker like brown paper typically used for crumpling for packaging filler so it won't be poked through), then wrap COMPLETELY in aluminum (tin) foil and seal all edges.
This step ensures you do not allow static to get to the board. DO NOT WRAP THE BOARD IN CLING WRAP and DO NOT JUST THROW IN WITHOUT WRAPPING as packing peanuts (unless Pink colored) will produce static build up and can zap the board.
2) Place the sealed board in something protective
a) This could be ideally a large flat box the same size or an 1" larger than the board with foam rubber on top and botton to hold it in. (The dimpled stuff works well)
b) If no box and foam rubber available, then wrap it in MULTIPLE layers of a medium to large bubble wrap (not the baby bubbles unless you want to use a ton if it). Ensure you have at least 1" of cushion around all sides, 2" is best.
3) Place the wrapped (in box or bubble wrap) board in a LARGER package. Ensure you provide at LEAST another 2" of space on EACH of the 6 sides. I repeat.. 2" around ALL sides. If you do not do this, then insurance WILL NOT COVER any physical damage to the board.
4) Tape heavy cardboard flat pieces perpendicular to the 4 thin sides of the board. This will prvevent the thin board/bubble wrap from sliding from side to side and ending up resting against an edge during shipping causing potential breakage and voiding of the insurance.
5) Fill the voids with PINK (anti-static) packing peanuts
a) Don't have pink? Then any other color (white=new, green=recycled, grey, etc...) will work so long as you sufficiently protected it against static damage.
b) Don't have packing peanuts? Then fill with bubble wrap or air-bags,. DONT USE CRUMPLED NEWSPAPER. This will collapse during shipping unless you severely overfill (and increase the weight considerably) and again, void the insurance.
If you follow these steps you will never have a board go bad during shipping, and if it's wrecked by box damage, you will be covered because you packed it correctly.
Amazingly, only about 10% of the boards I receive from eBay are packed this well. And only about 30% pack even partially close to the above list.
I just love getting a dual or tripple layer board stuffed in a 3" flat Priority mail box without an ounce of packing.... Usually one or more capacitors or other components are broken if not IC's.
Or the best I've got was a JR Pacman board wrapped in STATIC CLING WRAP and stuffed in a box with about 4 pieces of crumpled newspaper.