They like you to do a prompt pickup but delaying a week or so is acceptable, in which case do call to inform the owner, a very nice lady.
When you cross the border, let the border guards know that you are going shopping (do bring your passport these days). Open your package before you return and make sure all the parts are there and nothing extra. Declare the goods with value shown at the Canadian border and pay the GST/PST, and duty if the goods are not made in US/Mexico. Duty for Japanese electronics is normally 6%.
Shopping this way, people reported saving at least 40% buying a boat and a set of 4 winter tires.
If you live in other areas, you can use Google to search for UPS stores in the desired cities. Most UPS stores are friendly and reliable. For example, for UPS store in the Niagara Falls NY is:
1623 Military Rd
Niagara Falls, NY 14304
Phone: (716) 298-4461
Opening hours: 09:00 AM – 07:00 PM, closed on Sunday.
The store was rated “Very friendly and helpful” by other users.