If you are charged leaving Kelowna, you should have no problem reaching the Revelstoke supercharge. The actual distance is around 200 km (a bit more from my house, probably a few km less from the Kelowna supercharger). I measured this trip at 39 kWh in June 2014 with our 2013 S85.
You don't get very high travelling from Sicamous to Revelstoke. I think you top out at Eagle Pass (550m). You also hit that elevation travelling from Kelowna to Vernon. The road from Vernon to Kamloops through Falkland is actually 300 m higher. It's just that Three Valley Gap gets a lot of snowfall in the winter, in part because it is so low.
The biggest concern on the Kelowna to Revelstoke route is the traffic on Hwy 1 and road blockages due to slides (winter and spring) and construction in the summer (now).
One of the best L2 chargers in the province is outside the library in Sicamous if you get there and are feeling anxious.