The Pacific NW Church book covers southern BC and worthy of consideration.
CGs come and go but if you can borrow a 2013 and maybe even 2012 book you'll be good to go.
The book includes a website with updates but my experience: We arrived in Watson Lake expecting 3 CGs as listed and 2 were closed. I sent the Churches an email and received a reply that they had seen this earlier in the year but it wasn't listed in their online updates??? I never sent them another update. But it is a great and "must have" book - NOTHING else is even close.
The NW is a harsh environment with a very short tourist season. ALWAYS have a plan B as stores and CGs change. Just after we left Watson Lake the one CG filled up with a large caravan.