Advice about using an incandescent bulb as a heater is good. However they do emit UV so your stuff will decompose. Instead, put the bulb inside an opaque metal box.
In this case, "good heater" means "good enough for keeping condensation and mold down." But if you want to feel warm and toasty in the PNW, you'll need something with a bit more oomph.
Drafts are a big problem. My C27 has vents in the hatchboards, which we cover with canvas. She's also lacking proper shore power setup, so we run a power cable through a deck vent. Look around for avenues that cold air can use to spill into your boat.
As for storage space, I don't know what these guys are complaining about. If there's just one of you, you've got plenty of space, provided your life is not burdened with excess junk. The quarterberths on my C27 are massive; put the stuff you won't be using for a while all the way in the back -- but make sure they're in some sort of sealed bags. You can put those little packets of silica gel in the bags to keep the moisture down.
On my C27, we store seven sails inside the boat (plus one on the boom). With all that stuff we've still had enough room for weekend trips with four people and their stuff... and our friends always bring way more junk than they need. It was a squeeze, but it worked.
When Captain Vancouver was charting this area, he sent out 27' boats to explore all the little inlets. They had a crew of 14 men and would often be away from the ship for two to three weeks. I think you'll manage
Oh, the other things you don't always consider right away: where are you going to shower and do your laundry? You may be a bachelor, but still, once in a while would be nice... make sure you find a spot in a marina with appropriate facilities, and try to get a slip as close to those facilities as possible. It's a two-minute walk up the float from my boat to the nearest shower.