Last summer we sailed two 17' O'Day Daysailers around the Manicougan Reservoir, a giant annular lake in northern Quebec formed by an ancient asteroid strike (and Hydro Quebec's damming of the Manicougan River). 125+ mile, 8 day sail in a completely deserted lake.
If any one is interested, a link to the trip is below. I highly recommend this trip -- a lot of work, but totally worth it.
https://www.vtadventure.com/manicouagan