Greg I don't think you need a broker unless you are bringing it back commercially, the best thing to do is to call US customs and ask what the requirements are. If its like a car you will need to give 72 hrs notice so they can do a title search, then pay your taxes and you should be good to go.
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Under NAFTA if items are made in US, Canada or Mexico there should be no duty on them. You pay the sales tax into the area you are bringing the item.
A visit to a custom office before you bring it into the US might be the easiest way to find out what you require.