IMO, Internet surfing in the car is not very practical. The only use I see with Wi-Fi is real-time weather, traffic, and navigation updates. Another good use is wireless synchronization of your music and files while the car is parked in the garage.
I don't see lugging a laptop is practical either in the passenger side. With computers getting so small these days you may be better off with a nano-ITX computer squeezed into the glove compartment.
The 7" monitor can have RGB and A/V inputs. From there you have the option of connecting the rearview camera to your headunit or monitor (has 12V trigger to switch to rearview display). If you opt for touchscreen, the interface is USB. You can then hook up computer audio to one of the headunit AUX inputs.
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