Methods of creating vehicle physics changes dramatically from game to game. Often, as you have suggested, they focus on the body of the car and leaving the wheels as visual. The way I suggest going about this is using this system as a prototype, play around with what it can do and find the limitations, such as wheels clipping through uneven planes. This brings us to a second model, where wheels are the driving force. In this model you need to pay attention to a few factors:
_Where wheels are attached to the car body (since the body will move and control the movement of the wheel)
_Traction between the wheel and surface
_and finally the suspension
These are all key factors in determining the movement of the body and the wheels as well as their positions relative to each other. Good luck with the project, a complex system such as a car, is often difficult to replicate on a computer with any degree of realism or accuracy. So definitely start with the first model, since it is much simpler and can highlight key problems you may run into later.