Deadlands Preparation I

This winter, like the years before, we will play a three days game of Deadlands. It has become something of a tradition and although it takes place a week later than the previous years, I am already certain there will be a game next year and so on for the foreseeable future.
The role of Marshall (GM in Deadlands lingo)
is once again taken by me and so I am now planning the adventure.
Now, this has always been a daunting task for me, what with me being something of a complete failure when it comes to game preparation and planning.
It's not that I don't want to run the game or even prepare for it. It's rather that I just can't seem to concentrate on the work until I'm at home for crhistmass. Then I start reading all kinds of Deadlands books, usually while knitting some winter clothing. The problem with this approach is that
I usually end up with lots of random ideas and no coherent plot.
This year however, I'll try to improve on this. I know, I promised that the last times as well, but I'll try to
write about my progress and my approach in order to actually get a result.

I will, for the moment at least, refrain from posting any details of the adventure, in case any of my players read this and use it against me.
If anyone is interested and asks me about it, I might put up a write-up of the adventure afterwards. So without further ramblings to the matter at hand:

The facts about the adventure, or at least the ones I already know:
It should run for three days, I know the number of players and most of the characters they will play.
That's about it. What I want to achieve is a three-part adventure that has a complete plot and is absolutely awesome, so that the players want the year to go by faster in order to play again.
How will I get to this goal?
I have no idea, so watch me trying. The obvious advantage for you is that you can laugh at me, if I fail, without suffering my embarassment, when I wreck the adventure in front of my players.

Even before I start the preparation proper, I usually have a few ideas, very faint and disconnected, that float around. This year is no different in that respect and my first action will be to identify those ideas that make the most sense and are the most awesome.
Then I'll try to come up with a plot that can loosely be split into three parts. Each of these parts should feel like a complete adventure, but the first two should end with a cliffhanger to keep the players hooked for the next day.
The adventures also need a few sliding sections that I can remove or stretch out, depending on how fast the adventures run, to keep the time-frame.
After the first fixing of the plot, I need to decide on a location, if none is dictated by te plot itself.
After this it is time to write down more details concerning each adventure part, npc's, locations and so forth.
And then, hopefully, I have a finished adventure for thre days and enough time left to review it once and maybe even look for fitting background music.
That's the plan for now and this evening will be spent with the examination of the ideas I have and trying to make them fit into a whole.
We'll see how that turns out.