I'm waiting for the train at Lianyungang sStation. I'm waiting for the train at Lianyungang Station.

Since "station" is part of a proper noun in this case, it should be capitalized.

I'm waiting for the train at the Lianyungang station. I'm waiting for the train at the Lianyungang station.

If its official English name is “Lianyungang Station,” then capitalize “Station” and omit delete the “the” that I added.

I arrived an hour early, because after a three days' hike, I've been very tired. I arrived an hour early, because after a three day hike, I've been very tired.

I arrived an hour early, because after three days' hike, I've been{a three-day hike | three days' hiking | three days of hiking}, I'm very tired. I arrived an hour early, because after {a three-day hike | three days' hiking | three days of hiking}, I'm very tired.

“A three-day hike” means you did a single hike that lasted three days. The other two alternatives mean you hiked for three days, but not necessarily a single hike.

I arrived an hour early, because after three days' of hikeing, I've been very tired. I arrived an hour early, because after three days of hiking, I've been very tired.

I arrived an hour early, because after three days' of hikeing, I've been very tired. I arrived an hour early, because after three days of hiking, I've been very tired.

You’re in the present, so you’re now very tired. No need for an apostrophe you’re not missing any letters (it’s = it is) and there’s no possession.

I've captured some beautiful views in the past three days. I've captured some beautiful views in the past three days.

I captured some beautiful views in | over the past three days. I captured some beautiful views in | over the past three days.

I captured some beautiful views inover the past three days. I captured some beautiful views over the past three days.

I (saw/captured) some beautiful (views/landscapes/pictures) in the past three days. I (saw/captured) some beautiful (views/landscapes/pictures) in the past three days.