Stop the characters running away

So, with time on my hands I have decided to do what every self-respecting layabout does in times of unemployment - I'm writing a novel.

Actually, I've been writing a novel for some time, but this time I really am writing a novel. At least I've started, anyway - and I feel that should grant me a certain degree of kudos.

Now, there are several issues I have discovered with this line of work:-

1. It is unpaid.
Actually I sort of knew this before I started so it didn't come as too much of a surprise.

2. It is not easy.
Again, I sort of knew this one as well, but I had hoped that the difficulty was because I never seemed to have the time. It isn't. It is hard work, because...

3. Plots don't just happen.
This is new to me. I've written short stories and screenplays before and never had a problem with working out who needs to be where, when and why. Short stories are, well, short. This means that focusing on the story is pretty easy. Screenplays tend to be pretty fluid so, as long as the characters end where they need to be, they can pretty much be left to their own devices.
Writing something lengthy however, requires that I know what is happening from section to section, chapter to chapter. If I don't then something gets missed out or glossed over that is vital for events three chapters further on. As someone whose idea of planning is "start making the cupboard / chest of drawers /engine before reading the instructions, particularly the annoying bit which says, generally in big red letters 'read this first'" I find this somewhat irksome.

4. And this is the biggy, or at least the one that has the potential to cause major headaches the more I write. Characters Have A Life Of Their Own.
This one may sound odd to someone who doesn't write fiction, but it is true. I wrote a screenplay a few years ago for an animated film - it never actually happened but it was fun to write - and I was deeply impressed by where the characters led the story. They would do things on the page that I never planned. Sometimes these ramblings would lead to some really very good scenes.

However, I soon discovered that allowing this to happen in a novel leads, not to very good scenes, but to having to start again as the characters end up doing things for no reason or spending too much time doing things which are interesting but which advance the story not one iota.

I've had to start again three times so far. So, I've settled down and actually started a plot outline. It is quite complicated, and not a little scary. As it progresses I shall add more and more detail in the hope that when the time comes to really write it up I shall not have to spend too much time sat in front of the screen saying "ummm!" until I work out where to go next.

You never know. It might just work.