Write the name and address of the recipient on a card, and safety pin it to the quilt. Wrap the quilt in a clear plastic bag. If you don't use a metered box from the post office, use strapping tape and go all the way around the box in at least one place, (two are better) in both directions. This is in addition to taping the box closed along the entire flap area on the top and bottom. Look at the box and also tape the edges where the flaps meet the sides. You do not want there to be any loose place on the box that can catch on something. Write the name of the recipient in large print with a permanent marker on the box. Same with your return address. Request a signature.
The nice postal clerk will take your money for any amount of insurance you want, however, as far as collecting the insurance goes, you can only collect anything you have a receipt for. Materials, long arm quilting (get a receipt) or if you have had the quilt appraised by a licensed quilt appraiser. Otherwise, there is no way you can get paid for your time. Go to the PO site:
http://pe.usps.com/text/dmm300/609.htm
and read the last entry under:
"4.3 Nonpayable Claims"
Even if you use another carrier, the claims process is similar.