There are issues with a Canadian surveyor crossing the border to do work an American can do... probably not going to happen. There is a surveyor's society:
The Society of Accredited Marine Surveyors, Inc.® - (SAMS®)
You may find an accredited surveyor in the area you need.
You need not contact any American authorities vis a vis importing a boat to Canada. You are required to contact the Canadian Border Services immediately upon landing on Canadian soil (at a recognized port of entry) They will require you to go to a particular location (likely monitored by CCTV) and call them from there. Have the passports of all aboard in hand, they will ask you a number of questions and may or may not have you inspected. If they decide not to personally inspect the boat then you'll be given 3 days to pay duties (none if boat is North American built) and any applicable taxes at one of their offices. If you are immediately removing the vessel from the state you bought it you should not have to pay state taxes there (but this may vary, our experience is in WA state here in the PNW.)
This is a fairly painless procedure - don't recommend trying to understate the price paid to save a few bucks.. nowadays even they know about Yachtworld and Craigslists etc and so are more savvy about boat values than in the pre internet era...
In approximately half a dozen imports over a couple of years we were inspected on half the occasions.. the rest were phone exchanges only.
You must be arranging moorage for the new boat... try asking around at that facility for people willing/able/qualified to make that trip with you. If it's not a friend there will likely be some kind of fee.. and try to make sure the person is bonafide and will in fact be a help.
Shopping in the US provides a vastly greater selection, at least here in the west, which is probably the best aspect of it.. in addition with the dollar at near par the 'deals' are better than ever esp with the buyers' market that exists today. Since the US seems to be suffering more generally from the current economic situation than Canada there may be more distress sales south of the border.. You do need to factor in the costs related to travelling to these far locations to inspect the boat(s)... it adds up after a few fruitless trips...
All that said, though, I'd think Ontario should have a pretty extensive availability of suitable boats, and buying locally avoids all this issues with travel, distant surveyors & brokers, border crossings, etc etc...