P.S. A 36-foot Grand Mariner just got posted for sale in my region. I saw the ad less than 24 hours after it went up, but the seller had already re-edited it with "Sold! It's gone!" And you have to remember that up here, the marinas are right now shutting down for the season, not to open again for half a year. Hell of a boat market.
Now that's a hot market. As for the DeFever being a bit large for your region, yes, I would guess you don't see all that many boats as large. However, in 2018 we did the Great Loop. Best part was Canada, by far. Our chosen route was up through Lake Champlain, down the Chambly Canal to the St. Lawrence, on to Montreal, up the Ottawa River, down the Rideau Canal, the the Trent-Severn to the Georgian Bay. Nary a problem navigating any of your Heritage Canals even though the summer of 2018 saw very low water levels especially on the Rideau system. Our boat nominally drafts 4'9" but fully loaded we had to be at least 5' in that fresh water. We travelled the Trent-Severn with a 48-foot Krogen Whaleback that drafted at least 5' 6" so larger boats such as the DeFever can and do navigate the Heritage Canals safely.
As for buying a boat sight unseen, that is something that I would not do. But, the market being what it is some folks are obviously taking chances. When we bought our boat, yes, I looked at hundreds of boats on Yacht World before settling on a purchase of either a DeFever 44 or a Krogen 42. We ended up surveying four DeFevers before completing the purchase of our example. The previous three were not what they appeared to be on Yacht World. At the time when we were ready to buy, there were no Krogens on the market. Krogen 42s and DeFever 44s do not often come up for sale.
We really do not want to sell right now. We hope that the border opens next spring. We want to cross Lake Ontario from the Erie/Oswego Canals, go up to Ottawa on the Rideau, then to Montreal, then down the St. Lawrence to Quebec City, and then back to the States via the Chambly Canal and Lake Champlain. That was our cruising plan for this year but Covid wrecked everything. If the border is not open next season it is highly likely that we will sell the boat in the fall/winter, probably take it to Florida, have it surveyed for my own benefit and fix whatever shows up. I don't anticipate anything but minor oversights showing up in the survey as we have done so very much to the boat since we purchased her in Feb, 2014.
Good luck finding a boat suitable for your cruising plans!