Ideally the coffee would be in take away cup (I forget what you call this in america, my automatic translation is on the fritz) and you would be walking down a pier or along a beach. That gives you the activity Gaith so highly values in his Guide.
However not everyone lives near a beach and there is no alternative that is acceptable. Woods, bush, gardens.. all static. At the beach you have the constant movement and sussuration of the waves. This is a white noise and visual that lulls you into a sensate state of relaxation. It will take the edge off any anxiety or awkward gaps in the conversation. It is always perfectly acceptable to stare out at the horizon and toss crap into the sea, to cover awkwardness. If you have one hand permanently occupied with a paper cup of coffee so much the better.
And we don't go to the beach every day so this is something special, your date will enjoy being there even if she doesn't particularly enjoy you. It's a +5 environment.
Weather and geography conspire against most people though.