Not sure why you wouldn't just use the WiFi hotspot feature of the phone. While Windows is a nice OS for daily usage, it pretty much sucks for any embedded type of application like you are suggesting. Even if you did use Windows, driver updates wouldn't be an issue because the working set of drivers currently installed would continue to work without them having to be updated. The drivers are actually seperate from iTunes, and as long as the driver were installed, iTunes is not necessary. Also, using a WiFi card as an Access Point(hotspot) under Windows is very flaky, and even then only certain wireless cards are supported.
As I stated above, I use my iPhone USB tethered to a router with a USB port, and certain routers can even provide the WiFi hotspot for you(mine doesn't have enough memory to do both tethering and WiFi simultaneously) if you can't just use the iPhone's built in hotspot.
I actually use my setup in my truck, and have my router configured to provide a local hotspot for my tablet and laptop in my truck, while constantly watching for local free internet such as McDonalds or Walmart. When the router detects free WiFi(if I'm parked at Walmart or McDonalds, or my home or my friend's house) it will connect to the free WiFi and re-broadcast it over my hotspot instead of using the data on my iPhone. When I leave an area with free WiFi, my router automatically switches my hotspot's data source over to my iPhone. Works great!