Shotgun Open Missionary
Our female tester gave two thumbs up, only noting a small problem with clearance of her right leg, which was a little squished against the door, however the benefit of having the dashboard as a foot rest made up for it. Our male tester also gave two thumbs up, noting that the inclined angle of the seat made it more comfortable than the original, and that it took a few thrusts to figure out the optimal positioning.
Transitions
Put the seat forward a but and she can place her feet on the windscreen/windshield
But be careful. If she pushed hard with her feet when aroused she may pop the glass out!
I love this, but can't find any comfortable place to do :P
I've done this with my girl with a strapon (we're lesbians) it's great