This is a continuation ofrom my last entry.

The previous night, we searched for how to get to the nearest park, and found out we can go there byould take the subway there.

This sentence is fine, but this sentence is just closer to what you originally wrote in Japanese: "The previous night, we searched for the nearest park and found out we could take the subway there."

We were worried that to takeing the subway in New York would be dangerous for us, as tourists.

However, I was curious about the subway in New York, so we decided to take it.

This sentence is completely fine, but you could also write it this way: "However, since I was curious about the subway in New York, we decided to take it."

We bought the tickets from the Penn sStation forto South Ferry.

We bought the MetroCards and added $10 $to them.

I think you mean that each of you bought MetroCards and added $10 to each one, right?

After that, we went to see the Statue of Liberty.

The previous night, we searchedlooked up how to get to the nearest park, and found out we can goould get there by the subway.

"found out" is fine, but "learned" might be more natural.

We were worried that to take the subway inhe New York subway would be dangerous for us, as tourists.

Subtle difference in meaning:
"for us as tourists" makes it clear that you mean that the subway would be more dangerous BECAUSE you are tourists.
"for us, tourists" sounds like "for us tourists". The tone is slightly more casual if you say "us tourists", in my opinion, and the it makes the danger sound less serious. One is not better than the other, they have slightly different meanings.

However, I was curious about the subway in New York, so we decided to take it.

We bought the tickets from the Penn sStation forto South Ferry.

Ambiguous meaning: The meaning of "from" is ambiguous here. Did you buy the tickets AT Penn Station? Or, did you buy tickets (from anywhere) for a journey that starts at Penn Station? If you don't understand what I mean by this feel free to ask.

It was quite difficult for us to use the ticket machine, but we managed to do it.

We bought thea MetroCard and added $10 $to it.

We Took the Subway inALSO POSSIBLE: Using the New York Subway

The original title is also okay!

This is a continuation from my last entry.SUGGESTION: You could indicate this in the *title* of the entry, like this - ¶
Using the New York Subway (Part 2)

On the first day, we bought train tickets for the following day because we were planning to visit mya friend in Philadelphia.

After that(,) we went to see the Statue of Liberty.

NOTE: The comma is optional.

The previous night, we searched how to get to the nearest park, and found out we can go there by (the) subway.

NOTE: You can delete the final "the" in this sentence.

OPTION A: We were worried that to takeaking the subway in New York would be dangerous for us, as tourists.]¶
OPTION B: We were worried the subway in New York would be dangerous.

OPTION B is better than OPTION A because it is more succinct. However, OPTION A is also possible.

However, I was curious about the subway in New YorkNew York subwatys, so we decided to take one.

We bought (the) tickets from theat Penn sStation for South Ferry.

NOTE: The can delete the word "the" in this sentence.

It was quite difficult for us to use the ticket machine, but we managed to do it.

NOTE: You can safely delete the phrase "to do it."

We bought thea MetroCard and added $10 $.

After that, we went to see the Statue of Liberty.

The comma adds a natural break, and would generally be considered to be required grammatically.

We were worried that to takeing the subway in New York would be dangerous for us, tourists.

Change “to take” to “taking” to add a more natural flow to the sentence, and removing the comma at the end also makes the sentence flow better.

However, I was curious about the subway in New York, so we decided to take it.

The sentence isn’t completed until you add “it” even though it might seem redundant

We bought the tickets from the Penn station for South Ferry.

Station was just misspelt.

After that, we went to see the Statue of Liberty.

We were worried that to take the subway in New York would be dangerous for us, tourists.

The way you had it is correct with a comma, but it is a less common, stiffer way to say it. Ultimately, it doesn't matter, but it is more natural without the comma 👍. But, overall, a more natural way to say the sentence would be 'We were worried that taking the subway in New York would be dangerous for us tourists'.

However, I was curious about the subway in New York, so we decided to take it.

We bought the tickets from the Penn station for South Ferry.