Do you know about the
Air Forums B Van subform? If you have Interstate-specific questions, that's the place to be. If you want to keep tabs on developments in the Class B world generally, engage in model comparisons, and/or to ask questions about models that don't have good dedicated tech forums or users groups, THIS is the place to be.
In addition to Air Forums, I run
The Interstate Blog, which is dedicated to first-gen Interstate issues (2004-2007). As far as I know, it's the only closely-targeted blogsite out there.
There are a number of Air Forums threads on Interstate tires, including
this one, although I don't recall that anyone has explicitly asked about tires in the context of snow, other than regarding states with chain laws.
Once snow comes into the equation, competing priorities arise. While the T1N Mercedes Sprinter of which you are now the proud owner was designed for use in the snow, arguably many of its upfits were not. They are more fragile than conventional automotive components. Take a look at the construction of your under-slung wastewater tank, which will either be a gray tank or a combined gray-black depending on which model you bought. Imagine frozen slush accumulating on the sides and top of that thing. Imagine hitting slush clumps on a snowy road. As a blogger, I field email questions from people who have hit road debris including re-tread strips, asking me how to fix the resulting damage. Imagine what an ice chunk might do, if a re-tread strip can rip things off the underside of the Interstate chassis. Many of us simply decline to use our rigs in those conditions.