Well as someone else mentioned I dropped my blower motor (3 bolts), put silicone along the sort of ridge on the blower motor, drove to Vancouver from edmonton and no more cold feet! So hopefully that fixes it for the others but it made a massive difference on my truck.

 

A little update for anyone that cares.
This past summer and spring I had a water leak on my driverside. While chasing that issue, I sealed up a few spots and it seems to have helped a good bit.
First was the windshield mounting bracket. This is where the cowl attaches via pushpin. There's a gasket between it and the body, but it had just deteriorated. I put a whole lot of silicone around the bracket, essentially encasing it.
Second (and where my water leak was) is a body seam on the firewall in front of the parking brake. If you pull back the carpet and insulation, dismount the parking brake so you can move it, and wedge your head under the dash (I'm 6'2, so my feet were sticking out of the sunroof. My wife had a good laugh) you'll see the seam. Apparently the sealant had deteriorated and was allowing water in from a spot under the hood. I put a bunch of silicone as far up the seam as I could reach.
It finally got down to the 30's here, and even with wet feet, I was far more comfortable than previous winters. If I find anything else, I'll update again.