See the earlier posts where we advise that it is not possible to get the internet through the USB cable.If I plug the IPAD into the Cadillac USB port, will it connect to the internet through ONSTAR?
As KevinJS advises, besides wifi, some iPads (those with capability built in) can get internet through a cellular connection. It sounds as if you don't have this capability. If not, you are stuck with wifi. You can get wifi at your house with the correct router. Perhaps you have a friend with wifi? You can get it at starbucks. You can get wifi at McDonalds, Wendys, and Panera. Some cell phones can act as a wifi hotspot to which your iPad can connect. For a price, most cell phone companies are happy to provide mobile hotspots (Verizon calls them jetpacks, I think). Some cars now come with wifi built in (perhaps your Cadillac is one).