I live in BC, born and raised some 50 miles north of the 49th and started backpack camping spring, 1964. My favourite rig of several I own for your situation is my Western Mountaineering Terralite or Sequoia, depending on how late in the season it is and a full length Z-Rest Large plus an Exped Seven Large and a fleece sack full of clean duds for a pillow.
I have synthetic bags, very good ones, but, now mostly use down and have used various highend down bags even on the BC Coast, wettest region in North America, by actual measurement, for decades with NO issues. I seem to sleep better in down bags than synthetics and I also carry a light eVent bivy and Siltarp which all together works just fine.
