Kootenay Lake.
Theres lots of camping on the west side of the lake but if you go to a place called Woodburry Resort and Marina it's really nice. There is permanant sites where people keep there trailers all year round, then there is sites with full hookups for trailers and lastly there is tent camp sites right on the shores of the lake. There is also a resteraunt on site and boat rentals if your big into fishing.
Ainsworth hotsprings is just up the road to, which is a pretty neat hot springs. A lot more unique then most of the "hot pools" these days. Not to mention, you get to drive your car onto a boat to go accross the lake to get to these places.
http://www.woodburyresort.com/
http://www.hotnaturally.com/
http://en.wikipedia.org/wiki/Kootenay_Lake_Ferry