I have tackled the Canal du Midi twice, once as an out and back on Minervois Cruisers, going as far as Trebe before returning to Le Somail, and the second time as a one way beginning in Agde, and ending up in Carcassonne.
The experience is grand, and just being on the canal is rejuvenating. Be aware that October is a little late in the season, depending upon when you start out. It was chilly on the Canal in September (mornings and later in the evening) so be prepared for that. The Canal closes for the season on October 31, 2020, so take that into account.
I saw the beautiful line of trees near Trebes one summer years ago, but they are gone now, although the place isn't all that barren, because not all the trees were infected. Don't plan on swimming or fishing in the Canal--it's not that kind of place. Much good wine and food and of course, camaraderie with your fellow travelers. The Northern canals are probably less warm later in the season.
The cost of the boat is amazing--think about it as travel, sleeping accommodations, and entertainment--and shared between 4 people is very affordable. Not many Americans on the Canal, which was a real plus. This is how Europeans take their vacations, so you will meet some interesting folks. Oh, when choosing a boat, even though there are 4 of you, pick one which will accommodate at least 6, and preferably 8 passengers. You'll thank me for the extra room recommendation, because the boats are relatively small in the interiors. I would need at least 3 toilets for 4 people. A separate fridge for drinks would be nice, as well.
https://www.youtube.com/watch?v=1uJXFu_WxfU
