I just started using AE for about a year and I don't do keying often so forgive me if I sound amateur.
So I have footage of my subject in a car with a green screen in the background, my plan is to make it look like the car is moving. I filmed outdoor, my first problem is that the green screen is too overexposed, I did my best to adjust the exposure to make it look more green, but then my subject is quite underexposed, but i reckon i can correct that in post. But my green screen is still not really green and i'm having trouble keying it out.
Another problem is that due to filming space, the greenscreen is really close to the car and in some scenes there are nightmare reflections on my subject.
Remeber you will most likely have to do separate keys for different areas. And maybe just doing a simple mask deleting details, like in the back window of the last image will do, since the viewer won't know they were there to begin with.