SK here (so no first hand experience) but in the past couple of years we have had friends move to both Penticton and Rossland. Rossland would be my choice, because they still have winter, albeit WAY milder than here. And they have a ski hill:)
Ohh ohh ohh! Okay first...the fact that someone knows where Rossland is is exciting!
Here are my thoughts that I shared with OP when they first asked...My parents moved from Victoria to Rossland in search of a better life. It worked well for us, but I wouldn't recommend it now. House prices are inflated, in the top 10 in the province for municipal taxes, elementary school was closed down and the high school was made K-10 with grades 11 and 12 having to go to Trail. When we moved back to the area we decided on Castlegar....
Nelson is great but has a HCOL - It is much hillier and less bike friendly - doing anything downtown in the winter is tough it turns into a slushpuddle. It is also on the shore of Kootenay lake which is beautiful but it gets much less sun (except for certain areas more on the hilltop) so winters feel much darker and greyer...they do have more restaurants per capita then most cities, and most of them are pretty good so if you are a foodie it is great...not so much if you want to watch your budget :)
Castlegar is pretty easily accessible. I walk everywhere. Castlegar is a pretty long town so a bit of driving is required, depending on what you are looking for... Most of it would be bikable, I tend to measure distance in walkable though :) We do have snow, there is really no way around that in most of BC outside of the lower mainland. However we get substantially less snow than Rossland and have a much longer growing season. We also have an airport...but getting in/out in the winter can be dicey.
Castlegar sits in the middle between Rossland and Nelson so you get to take advantage of both communities. It has several options for schools and has a college as well. It is also cheaper for housing then either Rossland or Nelson, more job prospects than Rossland. Commuting to Trail in the winter down the hill is not fun!
We also have an awesome park along the river with walking trails, water pools and an almost finished bike terrain park. Syringa Provincial Park and the Arrow Lakes are 10 min away.
Trail - I wouldn't recommend if you have kids/family. The High school is not walkable/bikable for many locations. It does have the only hospital in the region though. The downtown core was decimated when Walmart moved to town - so there are lots of empty shops. Mr. Swick commented last time we were walking around that it looks a lot like East Hastings, there are some MAJOR drug issues. 15-20 or so years ago the province started moving welfare recipients from the lower mainland to Trail because it was so much cheaper to provide housing. It created a whole bunch of social problems that have firmly taken root and actually seem to be growing.
So that's my two cents, the Koots are awesome though, I highly recommend this area :)
Oh...to respond to totoro - Rossland has Nancy Green lake about a 20 min drive away. Christina Lake is about an hour ( about the same distance from Castlegar)
OP - any updates?