is it possible to somehow start a new flight with a 737-600 being cold & dark at a gate, not having the engines running? currently i'm loading a saved flight where I have shut down the plane and then choose the airport, time, weather, ...

Go into Select a Flight/Choose a Category/PMDG/ and you will see cold and dark. Select it, then select an airport and gate location and anything else you want save it and you are all set. The flight is save in My Documents/ Flight Sim Files on your hard drive. If you like to start with the present day and time rather than when you saved it, you can go into the Saved Flight File using Notepad ( don't just click on the file, cause all that will do is start the flight) for that flight and delete the lines of information that are listed under (time date season) That info is what forces FS9 to load using the time , date, and season that was present when you saved it. Without that information in there, FS9 will default to the current time, date and season when it loads the flight. Just don't resave that flight anymore, or else FS9 will recreate the lines of information and you will have to go in and delete it again. By the way, all the saved Flight Files on my PC have an Airplane Icon next to them, to make them easy to find.

There's also a default adventure script by Ben Chuchra (fltsim.flt) posted on the AVSIM library that replaces the default startup script, and shuts down all circuits and systems before you load any situation.This file is located in your Flightsother folder from the main FS install folder. If you're interested in how to modify it, such as setup your default start location, you can d/l the Adventure SDK which includes the reference doc for the contents of these scripts.