kondo zikan ga aru toki, eki no tikaku no bukken wo mou itido mi ni ikukoto ni simasita.

In this sentence, 今度 most naturally means next time / on a future occasion / when I get the chance soon.

今度 can be a little flexible depending on context:

• this time
• next time
• soon / one of these days

Here, because it is followed by 時間があるとき (when I have time), it points to a future opportunity, so next time or when I get a chance fits best.

Because ある before とき refers to the time when I have time in a general or future sense.

A useful rule:

• dictionary/plain present form + とき = when doing / when about to do / when one does
• past form + とき = when did / when had done

So:

• 時間があるとき = when I have time / whenever I have time
• 時間があったとき = when I had time / when I happened to have time

In your sentence, the speaker is talking about a future plan, so あるとき is the natural choice.

時間がある is a very common pattern meaning to have time.

Literally, it is closer to:

• time exists

That is why が is used: it marks the thing that exists.

So:

• 時間がある = there is time / I have time

You may also hear 時間はある, but that changes the nuance:

• 時間がある = neutral statement of having time
• 時間はある = as for time, I do have it (often with contrast or emphasis)

時間をある is not correct.

This is a noun phrase built step by step:

• 駅 = station
• 駅の近く = the area near the station
• 駅の近くの物件 = the property that is near the station

So the first の connects:

• station → nearby area

And the second の connects:

• nearby area → property

A natural English breakdown is:

• the property near the station

Also, 近く behaves like a noun here, which is why it can be followed by の.

物件 is a real-estate word meaning property, real-estate property, or sometimes listing.

It is broader and a bit more formal than words like:

• 家 = house
• アパート = apartment building / apartment
• 部屋 = room
• マンション = apartment/condo building

So 物件 is often used when talking about places to rent or buy, especially in housing searches. It can refer to:

• an apartment
• a house
• a condo
• a real-estate listing in general

This is the grammar pattern:

• verb stem + に行く = go to do something

Here:

• 見る = to see
• verb stem = 見
• 見に行く = go to see

So the に marks the purpose of going.

Other examples:

• 食べに行く = go to eat
• 買いに行く = go to buy
• 会いに行く = go to meet

In your sentence, 物件をもう一度見に行く means:

• go see the property one more time

Because with に行く, Japanese uses the verb stem, not the full dictionary form.

So:

• 見る → stem 見
• 食べる → stem 食べ
• 買う → stem 買い
• 読む → stem 読み

That gives:

• 見に行く
• 食べに行く
• 買いに行く
• 読みに行く

So 見るに行く is not the standard form.

Because 物件 is the object of 見る, not the object of 行く.

The structure is:

• 物件を 見に 行く
• go to see the property

So:

• 物件を belongs with 見る
• 行く is the main movement verb

This can feel tricky in English because go is the main verb of the whole phrase, but inside that phrase there is still another action, seeing, and 物件 is the thing being seen.

もう一度 means one more time / again.

In this sentence, it modifies 見に行く:

• 物件をもう一度見に行く
• go see the property one more time

Its position is natural because it comes right before the action it is modifying.

You could think of it as:

• the property
  • one more time
    • go see

〜ことにする means to decide to do something.

So:

• 行くことにしました = decided to go

This pattern is very common and natural in Japanese.

Breakdown:

• 行く = to go
• こと = turns the verb/action into a noun-like idea
• ことにする = decide on doing that action
• ことにしました = decided to do it

Compared with 行くと決めました:

• 行くことにしました sounds very standard and common for personal decisions
• 行くと決めました can sound a little more direct or emphatic, like I made up my mind that I will go

So both can mean something similar, but ことにしました is especially common for stating a decision.

This is a very important distinction:

• 〜ことにしました = I decided to do it
• 〜ことになりました = it was decided that... / it has been arranged that...

So:

• 見に行くことにしました = I decided to go see it
• 見に行くことになりました = it has been decided/arranged that I will go see it

The first sounds like the speaker made the decision. The second sounds more like the decision came from circumstances, discussion, or someone else’s arrangement.

The subject is omitted, which is very normal in Japanese.

From 〜ことにしました, the listener usually understands that the speaker is talking about their own decision unless context says otherwise.

So the implied subject is most likely:

• I or possibly
• we

Japanese often leaves out subjects when they are clear from context.

They are very close. In this sentence:

• 時間があるとき
• 時間があるときに

both can work.

The に after とき is often optional, especially in everyday speech. Without に, the sentence sounds a bit lighter and smoother. With に, it can sound slightly more explicit.

So here, とき alone is completely natural.