I have both lenses with a 5D3 and a 7D. I shoot mostly sports and indoor events. The 70-200 is my prefered lens for most of what I shoot. The sports part is easy. But even with candids, I like to shoot from across the room and this lens is great.
But, the 24-105 is still essential. It sounds like you want both at some point. Get the 24-105 now, it's only costing you $630 as part of the kit. Getting it later will cost you closer $1,000. Plus, I suspect this lens will fill much of your current needs with the automotive shots.
FWIW, I often carry the 5D3 with the 70-200 and the 40 pancake when I "travel lite-ish".