Welcome to the forums! Hope you enjoy all the great info available here. Not trying to be a smart aleck or anything here, but is there any way you could avoid driving at all at least on some days since you're going less than a mile? Could you bundle up and walk or use public transit? The kind of driving you're describing is a high wear situation for an engine because contaminants don't boil off as well since the engine doesn't warm up much. So the more you avoid driving those short trip miles, the less wear there will be on your engine (and the rest of the truck, for that matter). It looks like you're in WI so I know it's very cold now, but your vehicle will not get you very warm unless you run it at idle for 5 or 10 minutes before you drive. Not sure where you are in WI, so alternative transportation may not work for you if you're not in a city.
I would recommend you use some sort of synthetic for your application. I'm not familiar with Schaeffer from personal use, but their synthetic will probably work well. You might also consider Amsoil, Mobil 1, or Pennzoil Platinum, all of which get good reviews here on BITOG. The synthetic will flow faster and lubricate more quickly, which is what you want for an engine in a cold climate.