As Matt pointed out, the Swiss de-registration of the aircraft with
paperwork being sent to the FAA is the most important part.
Also be certain to have good title documents for the trailer. I've
found this to be the biggest pain about buying most gliders. Very few
seem to care about trailer documentation.
Then it's just a matter of getting the new documentation from the
FAA. They will have received the deregistration documents from CH.
Apply for the N-number on the FAA website in advance, and start the
paper trail with your local FSDO.
If you want to drive the trailer out of the docks you may need a
plate. Somehow registering the trailer before it arrives is best.
Build and test the electrical adapter and be certain you have a 50mm
ball, unless you've got a 2" coupler for the trailer.
Getting the shipping done and customs clearance is easy if you hire
the right people. Get several quotes on the shipping. My last shipment
ended up costing just over half of what the highest bidder quoted.
Prior to shipment, discard the main batteries (small memory
batteries in flight computers, radios, etc are OK) and remove any
cleaning fluids, adhesives, etc (HAZMAT) from the trailer, and clean
the glider and trailer completely inside and out. Also use a spray
insecticide in the trailer. You don't need to be charged for
professional cleaning and quarantine.
To get a few dollars toward the shipping, you may want to put
somebody else's stuff in the trailer or container if you are using one
(consolidation). If you do this, include that stuff in the paperwork.
Jim