I woke up to a cloudy day, seeing from the window that the white sky was on the (peaks/edges of the head of hills).

We don't describe any part of hills as a "head", I think you might mean the peak or the edge depending on which angle you were looking out your window from.

Cars drove on roads and people walked in streets - it was the end of my journey.

I planned a leisure walk in town.

However, it was a pity I was not able to going to the national park in Nelson.

Then I soakimmersed myself into the public library.

"soaked" is nearly always used literally. If you want the metaphorical meaning, immersed is better.

Last dDay in Nelson

I woke up to a cloudy day, seeing from the window that thea white sky was on the edge of the head of hillabove the hilltops.

Cars drove ondown the roads and people walked in the streets - i. It was the end of my journey.

I planned a leisure walk in town.

I would likeanted to enjoy the city’s special vibe .

However, it was a pity that I was not able to going to the national park in Nelson.

Then I soakimmersed myself into the public library.

But, I never went to the art galleries because I think it is a waste of time.

Anyway, I felt pleased about this journey.

You use "anyway" to redirect yourself to a previous topic when you've gone off on a tangent. You never strayed from the topic, so the "anyway" feels redundant here.

I woke up to a cloudy day, seeing from the window that the white sky was on the edge of the head of hills.

Not quite sure what you mean by the very last bit. You could the white sky above the tops of the hills, I assume. I think a more natural sentence would be: "... seeing the white sky above the hilltops."

I planned a leisurely walk in town.

However, it was a pity notto not be able to going to the national park in Nelson.

Or: It was a pity that I was not able to go...

Then I soakimmersed myself into the public library.

"soaked" sounds too literal here, like you're getting wet.

Anyway, I felt pleased about (or "with") this journey.