Request: General Information on CAN (2012 Altima)

As an owner of a fairly new car, I am somewhat disappointed on the available features my car has. I feel the automotive industry has in many respects, made very little improvements to their vehicles over the years. Many people may dispute this claim, but I'm not here to argue about what the automotive industry has done. Instead, I am here to learn about what kinds of things are controlled by the CAN bus, specifically on my 2012 Nissan Altima. I am interested in messing with just about everything that doesn't affect my driving experience/control of the vehicle. I am fascinated by DIY projects for vehicles such windshield wipers that function automatically based on weather conditions. I really like the idea of having a touch screen in my vehicle (something it does not have right now) for the purpose of navigation, entertainment, and maybe lots more. But I don't like the idea of an already manufactured radio with built in navigation. I would much rather satisfy my curiosity in technology by doing things myself. I am here looking for advice on a starting place for my project. What should I look into? What might I be able to do using CAN? Do I share this interest in my vehicle with anyone else? I am looking forward to hearing from YOU.

Best regards,

Randy