The docking station should make things easier especially if it has a power button built in that you can hack. That should make things really easy to bring back into the house. Also If you can try to find a cigarette lighter adapter that works for your laptop, your install will probably be more reliable and energy efficient. Plan on getting some sort of USB sound solution, name brand like turtle beach would probably be the easiest to implement, just remember to use the included drivers for less out of the box hassle with that. This can also allow you to avoid more interference problems by having the USB sound card up front and the laptop in the trunk. You may also want to look into some other kind of auto turn on function for the laptop, you can try some kind of wake on lan solution, or the auto turn on module sold on this board. Some people might tell you different, but this is coming from my experience with using two different laptops in my car, everyones install is different, so search and se what others have done.
(If I had a laptop that had a good dock with a hackable power button, and an easily sourced cigarette lighter adapter, i would probably stil be using a laptop, but mine was sort of a one off (old emachine, but one of the good ones))