Welcome! I live just south of you in White Rock. This past winter was exceptional by recent standards. The snowfalls we had at the start of each month from Dec-Mar really contributed to the messy roads. There is much more sand and dirt on the shoulders than most years, and at least down in my neck of the woods there has been little street sweeping. Honestly, this stretch from Oct 2016 to now has been the worst since I moved here in 1999. At least Oct and Nov were warm rain.
IMO, what you really need here is your dry day princess bike, which you have covered with your C60 (I have one as well
). Then you need a dedicated winter bike with full fenders and flaps, just as Calnago describes. All other bikes are then just variants of these two primary bikes, "the dry day winter bike", "the travel bike", "the old race bike I won't get rid of", etc, etc. The trick is not to cheap out on the winter bike. You are going to ride it A LOT in this climate, so you want it to be something you enjoy riding. You have to accept that it won't be light, the fenders kill that buzz. My personal winter bike is a Hampsten Cycles Crema that I had built in 2011. It is steel, with a steel fork, long reach brakes and clearance for full fenders and 28 mm tires. Built with a mix of 10spd Dura-Ace/Ultegra. I've put over 30K km on this bike and I love it but this past winter has cracked me with respect to the dirty roads and brake pad/rim wear. I'm now planning a disc brake version of a winter bike for this autumn. Looking at options like the Domane, the Niner RDO RLT, but honestly I will likely be going with a custom Breadwinner B-road out of Portland. With disc brakes I can use a full carbon clincher if I want to, and not feel guilty about about killing braking surfaces. For me, I'm not too concerned about matching ride/geometry to my other bikes, I want good fender clearance and easy fender mounting as my priority. As long as the geometry is close I can get my position sorted out. The Hampsten will likely have its fenders removed and become a "gravel bike" or a "dry day winter bike".
Just be sure if you are building a dedicated rain bike to use with full fenders that you are not compromising on the fender mounting. A bike with proper mounting will require much less fender maintenance (the worst maintenance of all!) and give enough clearance to run some larger tires.
EDIT: Just caught the part about you living in Maple Ridge. You live in a great place for riding, some of my fave roads in the whole area are from MR over towards Mission and into the Hatzic area. So many options, up and down, and relatively quiet though a lot of hillbillies in big trucks in spots (Dewdney Trunk). Honestly, the roads are not normally this horrible, this past winter was awful. Hope you are out riding as I type, I am stuck at work reading WW on lunch break.