Hello Allan,
I did a similar trip last weekend, starting a Georgetown, ON, which is similar distance to Kingston. I recommend stopping at Port Hope for a quick top up, while you grab a coffee or water at the local Tim Hortons. Then I stop in Kingston for a short lunch or dinner. In this way, you can avoid doing a range charge, and really don't have to worry about energy consumption. I have done the trip several times before the Port Hope supercharger, but I did have to watch my consumption more carefully.
In Ottawa, I usually stay at the Brookstreet hotel in Kanata which has 2 Tesla HPWC and 2 J1772 chargers. This makes for a stress free Tesla road trip experience. There are a couple of spots downtown, but I don't know of any non-hotel location where you can charge overnight. If you don't know where you are going to charge in Ottawa, and how much charge you are going to get, I'd recommend doing a full range charge in Kingston and travelling to Ottawa via the back roads (road 10 via Westport and Perth) to minimize your consumption. Depending on your usage in Ottawa, you may be able to get back to Kingston without any additional charging.
Good luck with the trip.
David