Natural is always good, and I find that is a really interesting factor to maintain as a writer. However it can be a double-edged sword as experience has shown.
You want the character to progress, well, naturally with the environment and characters shaping them and what happens in due course. But not everything can be natural, and when factors outside of Chaos come in sharply like writers leaving, getting bored of their character or anything, it leaves you stuck. You could be about to start a thread or mid-way throug a big one....and then RL strikes.
That's when being natural is tricky, as you have to be UN-natural sometimes to take your character out of what was shaping up and suddenly stopped. While this can be seen as REALLY natural, we all know some sort of expectation and planning is evident, so it can knock you for a while to regain footing with your character after getting so absorbed into a path that now must stop and logically be explained as to why.
So while natural is good, and also pre-planning certain ideas and locations and settings, the outcome is best to find organically.
I also have learnt not to be too hard on yourself if things don't work - nothing is worth getting frustrated, annoyed or angry about that may lead to IC/OOC fall-outs. We are all passionate writers, but we all can't 100% guarantee natural progression is as easy as it sounds on paper.
Just enjoy it. Enjoy the writing, enjoy the fictional fun and don't stress about it. YOU are in charge of your character and must remember that you can change things anytime to make it easier.