I can offer up a few additional tips.
First, get Cheryl Barr's Downeast Loop book. It might be out of print, but can be found with a little effort. It's a bit out of date, but still includes important info and is a key element in your library. Of particular value are her tips for planning a few of the more complex legs where you have no stopping point and can only make the leg if you plan the currents. She makes it very easy by giving departure times relative to key tide marks.
Jeff probably already knows this, but ActiveCaptain is a key resource as well. But from Quebec City to around Halifax you will find very few reviews. Mine probably represent 20% of the total which is pretty bad. Regardless, they are another key element of information.
For anyone cruising the US, the Quebec to Halifax part of the trip, which, by the way is approximately 1000mn is very remote. But don't shy away from it. It does require a little planning, but there are plenty of stops and fuel is not a problem - it just requires a little planning. It's not a trip that you can just bumble through, but poses a nice step up in challenge compared to the Great Loop or coastal cruising.
The people aren't French, they are Canadian, but they speak French. If you can learn at least a little bit of French it will serve you well. Even if you can just say that you don't speak French and ask if they can speak English, most happily will and great you with open arms. The people area really great. But if you just plow through in English you will likely offend a few people. You also will find a few places where nobody speaks English, but people still manage just fine. By the way, if you speak French, don't assume you will be able to understand anything the Quebecois say. The pronunciation is quite different. The only time I was able to really understand someone was in a restaurant in Quebec City, and it turns out the lady was Parisian.
Don't miss the Saguenay River and Baie D'Eternite.
We skipped the Bras d'Or lakes, but I gather it's spectacular. We were just tired by then, and it's not to far for us to reach on another trip, so we saved it for another time. If you are not from New England, I would not miss it.
Jeff is right about doing the loop clockwise. Much of the St Lawrence current is ALWAYS flowing outward, so going the other way is much more difficult. Plus, the point about the seasons favoring a clockwise trip are very true.
For the inland part of the trip from Albany to Montreal, there are three different routes you can take. They are:
1) Go north through the Champlain Canal and Lake to Sorrel. From there you can backtrack up the St Lawrence to Montreal, or just turn right and head to Quebec City. But Montreal is really nice, so I'd backtrack.
2) Go west our the Erie Canal to the Oswego Canal and into lake Ontario. From there you head up to Kingston ON which is right at the beginning of the St Lawrence. From there, you have another choice.
2a) Go out the St Lawrence through the Thousand Islands region and run through the locks to Montreal (last lock is there). The Thousand Islands are beautiful, but the locks are tedious. Commercial traffic takes priority, and you can sit and wait for hours to get through. It makes trip planning difficult, even if you don't mind waiting.
2b) Go up the Rideau to Ottawa, then take the Ottawa river back down to Montreal where it rejoins the St Lawrence. The Rideau is really cool and I highly recommend it, but you need 5' or less draft. And if you are over 4' you are supposed to tell them ahead of time. We had no trouble with 4'. You will still have two of the big locks to go through to get around Montreal, but you will bypass 5 others, so I think this route is the best. You will, however, go through 45 locks or so on the Rideau, but they are small and very pleasant. Once downside is that you will miss the Thousand Islands, but we solved that by spending two days exploring that area before running up the Rideau.
From Montreal/Sorrel, it's all the same route.
I'm sure there is more, but this should get you started, and hopefully motivated to make the trip.