We say, "railway track," but actually there is no such thing. Sincerity itself is the railway track. The sights we see from the train will change, but we are always running on the same track. And there is no beginning or end to the track: beginningless and endless track. There is no starting point, no goal, nothing to attain. Just to run on the track is our way. This is the nature of our Zen practice.
You should get rid of excessive things. If your practice is good, without being aware if it you will become proud of your practice. That pride is extra. What you do is good, but something more is added to it.
To be natural is something we must work on.
naturalness is, I think, some feeling of being independent from everything, or some activity which is based on nothingness. Something which comes out of nothingness is naturalness, like a seed or plant coming out of the ground. The seed has no idea of being some particular plant, but it has its own form and is in pefect harmony with the ground, with its surroundings. As it grows, win the course of time it expresses its nature.