Careful on the fax assumption - requirements vary based on the POE. Check the CBP website and confirm info via their recorded line. You're going to Ontario, but don't say what border crossing you are going through. If you are crossing directly into Ontario, I believe you have 4 options:
- Alexandria Bay (on the way up to Ottawa) - requires you to mail them the original title (export office open M-F 8-4pm)
- Lewiston (near the Niagara Falls) - requires you to e-mail them the VIN number (export office open M-F 8-4pm)
- Ambassador Bridge (Windsor area) - requires you to mail them the original title (no export office per se; any officer can export 24/7)
- Blue Water Bridge (Sarnia) - requires you to fax them copy of title (export office open Mon-Thurs 8am-8pm, Fri 8am-noon)
You can confirm info on each port at http://www.cbp.gov/xp/cgov/toolbox/contacts/ports/ny/0708.xml - under supplemental info they have detailed instructions on how to export vehicles (they also have the vehicle export phone number listed for each port).
Note - they all require receiving information a minimum of 72 days prior, so if you are mailing it give yourself an extra buffer (there's no harm in sending info in super early)