As far asFrom what I know, people like to go to mountains in fall seasonduring the fall. From what I know, people like to go to mountains during the fall.

As far as I know, people like to go to mountains in fall season. As far as I know, people like to go to mountains in fall.

It's not necessary to say "fall season" since it's understood from context :)

ItThis is because people can see the beautiful maples rather than other plac trees. / This is because people can see the beautiful maple leaves. This is because people can see the beautiful maple trees. / This is because people can see the beautiful maple leaves.

(It is) because people can see beautiful maples rather than other places. (It is) because people can see beautiful maples rather than other places.

By my count, there are more 70% of the aKorea is covered by mountains in Korea. By my count, more 70% of Korea is covered by mountains.

By my count, there are moremore than 70% of the aKorea is covered by mountains in Korea. By my count, more than 70% of Korea is covered by mountains.

This sounds better :)

So people can goThese days, many people travel to the mountains for maple-viewing these days. These days, many people travel to the mountains for maple-viewing.

So people can go to the mountains for maple-viewing these dayto see maple trees. So people can go to the mountains to see maple trees.

Maple viewing in english sounds odd, so I'd suggest just saying "to see x" :)

I think, this week is one of the best dayweeks to go maple-viewing . I think this week is one of the best weeks to go maple-viewing .

I think, this week is one of the best days to go maple-viewing see the maple trees. I think this week is one of the best days to go see the maple trees.

On tThis weekend, I am going to go to a mountain with my family to take pictures of the leaves. This weekend, I am going to go to a mountain with my family to take pictures of the leaves.

On this weekend, I aI'm going to go to athe mountains this weekend with my family to take pictures of leaves. I'm going to go to the mountains this weekend with my family to take pictures of leaves.