It's been a few years but I remember the process as being fairly easy, after you understand it. The aircraft part is fairly straightforward.

The Trailer is a bit tricky. Get a separate bill of sale for the trailer. Keep the Canadian tag on it, take the Canadian title with you. Drive it home, take the Canadian title (registration) & the bill of sale to your local DMV. Get a US tag & title for the trailer. Mail the Canadian tag back to the Seller in Canada so that they can turn it in. Getting a US tag for the trailer, even if you state does not require one, will help you with re-sale.
Most US banks can get you a "Cashiers" check in Canadian funds for your Canadian seller. It's not may not be called a Cashiers check, the bank will know what you need. as I said it's been a while.

Calling the aircraft registration guys at the FAA was helpful. You need the forms (including the Canadian De-Registration docs) & documentation to register the aircraft, and then another set of forms to get an airworthiness inspection & certificate. Looks like most of that is done online now.

Understand everything required before you go to Canada, including making sure you have insurance on the trailer & the glider in advance of taking it home.