It is reasonable to be concerned about shipping your instrument across the country, but after doing business this way for a number of years, it has never been an issue. I trust UPS over other companies because at any time you can see where your package is located. Also, their insurance virtually eliminates any risk of loss, and it is very inexpensive. I, personally, would advise against using the U.S. Postal Service.
Make sure your clarinet is tight in its case. If not, use bubble wrap to fill any gaps.
Choose a sturdy and preferably new box that provides at least 2" of clearance on all sides of the case.
Bubble wrap the case (use the bubble wrap with large bubbles) and float it in packing peanuts. Don't use newspaper!
Any UPS or FedEx location can pack your instrument if you don't have the proper materials.
Pre-Paid Box Service
I'll send a pre-paid, insured box with packing peanuts to you. All you have to do is place your clarinet in the box, seal, affix the label, and drop off at any UPS location.
To Request a Pre-Paid Box
your name, address, and phone number, along with the size of your case, and the desired insurance amount. There is no charge for the box, and the return shipping will be billed to you when you pay for the repair work (usually only $29 with $1000 insurance).