Living in MI isn't much different than PA this time of year. If temps are going to get down to 10degrees or lower, it's a good idea to plug in the truck for the block heater. That will make it easier on the high pressure oil pump, and the low pressure oil pump. The injectors are hydraulically fired by engine oil, and if it's REAL cold out, the truck will romp at startup until the colder oil is cycled through(just a few seconds). I've never used much additive, and haven't had a problem with gelling yet. When I do use additive, I prefer to use Stanadyne products instead of Diesel Kleen. Just personal preference.
Another good idea is to find a station with a high turnover rate on the diesel fuel they sell. You don't want to get old possibly watery fuel at all if you can help it. I like to use ones that are frequented by big rigs, you know they are taking 100 or more gallons for a fill. Make sure to get underneath that truck and open the water separator plug at least once a month. THere's a different plug you can get from online retailers, or International, that has a larger knurled head that you can finger tighten instead of fight with an allen wrench in the standard plug, especially if your truck is 4X4. The front driveshaft is right in front of the drain plug.
There really isn't a whole lot in terms of regular maintenance on these trucks, even if you decide to do it all yourself. I do change the oil and filters at home, just because I like to get under the truck and take a good look at everything to hopefully catch things before they become major problems.
