About those public chargers - you need the adapter that came with the mobile charger, right? And how fast are those?
If you are talking about Level 2 public chargers, yes you generally need the adapter. However, there are also 'destination' Level 2 chargers in some locations that use the native Tesla plugs, so no need to use the adapter there. That said, using the Level 2 adapter in the Tesla has never given me an issue.
If you are talking about Level 3 charging, then unless you have a special CCS adapter - not officially supported yet by Tesla in North America, but some Tesla owners have imported the adapters from Tesla Korea - then you are 'limited' to the Tesla Supercharger network. But that is not much of a 'limit'. Tesla Superchargers are excellent and well spaced along that route, though they can sometimes get a bit busy during peak times.
Consider taking the Toronto-Perth route along Highway 7, charging at the Perth Supercharger, then Perth-Tremblant, via Ottawa. That will give you sufficient charge to reach Tremblant with lots to spare. Alternatively you could stop earlier at the Peterborough Supercharger and then top up briefly at the Ottawa (Bell's Corner's) Supercharger before heading on through Ottawa to Tremblant. Other options are along the 401, of course, but that would not be my own first choice.
As for the route from Ottawa, you could cross the King Edward Avenue (Macdonald-Cartier) Bridge in downtown Ottawa to the Quebec side, take Autoroute 50 to Montebello, and then Highway 323 to St. Jovite/Tremblant. Another option is to continue along 417 and then Highway 17 east of Ottawa and take the ferry to the Quebec side at Cumberland or at Clarence and then connect to Autoroute 50 that way. The Cumberland ferry departs very frequently as there are many of them going back and forth. The Clarence ferry is a cute little electric ferry - thematically suitable for a Tesla trip - but there is only one of them so you may have to wait a bit depending on your timing. Both ferries can get busy and thus backed up at peak times during holiday weekends so I would avoid them then, but otherwise are fine.
Relax, enjoy. It is an easy trip, and a nice one.