asita no ryokou no sitaku wo hayame ni site okimasu.

A natural breakdown is:

• 明日 = tomorrow
• の = links nouns, like for / of
• 旅行 = trip, यात्रा? no, in Japanese just trip / travel
• の = another noun-linking of / for
• 支度（したく）= preparations, getting ready
• を = marks the direct object
• 早めに = a bit early / earlier than usual
• して = do in て-form
• おきます = do in advance / do beforehand

So the structure is basically:

[tomorrow’s trip] + [preparations] + early + do in advance

A smooth English translation is something like:

• I’ll get ready early for tomorrow’s trip.
• I’ll make preparations early for tomorrow’s trip.
• I’ll get everything ready ahead of time for tomorrow’s trip.

Because Japanese often chains nouns together.

Here:

• 明日の旅行 = tomorrow’s trip
• 明日の旅行の支度 = preparations for tomorrow’s trip

So each の connects one noun to the next:

1. 明日 の 旅行
   trip of tomorrow → tomorrow’s trip

2. 旅行 の 支度
   trip’s preparations → preparations for the trip

Put together, it becomes:

• 明日の旅行の支度 = the preparations for tomorrow’s trip

This kind of noun stacking is very common in Japanese.

支度 is read したく.

It means preparation, getting ready, or arrangements. In daily Japanese, it often has a slightly practical, everyday feeling:

• getting ready to leave
• packing
• arranging what you need
• making yourself ready

準備（じゅんび）also means preparation, but it can sound a little broader or more neutral.

For example:

• 旅行の支度 = getting ready for a trip, packing, making practical preparations
• 旅行の準備 = preparation for a trip in a broader sense

In many situations, they are close in meaning, and either could work. But 支度 often feels a bit more like actual readiness or practical getting-ready.

Because 支度する behaves like a noun + する expression.

• 支度 = preparation
• する = to do

So literally:

• 支度をする = to do preparation
• more naturally: to get ready / to make preparations

The particle を marks 支度 as the thing being done.

This pattern is very common:

• 勉強をする = study
• 掃除をする = do cleaning
• 準備をする = make preparations
• 支度をする = get ready / prepare

早めに means a little early, on the early side, or earlier than usual / earlier than necessary.

It comes from 早め:

• 早い = early
• 早め = somewhat early / on the early side
• 早めに = early-ish / a bit early

So:

• 早くする = do it early
• 早めにする = do it a bit earlier than usual / give yourself extra time

In this sentence, 早めに sounds very natural because it suggests planning ahead and not waiting until the last minute.

So the nuance is not just early, but with a time cushion.

This is one of the most important parts of the sentence.

〜ておく often means:

• to do something in advance
• to do something beforehand
• sometimes to leave something as it is, depending on context

Here it is the in advance meaning:

• しておきます = will do it beforehand / will get it done in advance

So:

• 支度をしておきます = I’ll get ready in advance
• 早めにしておきます = I’ll do it early / ahead of time

This is different from just:

• 支度をします = I’ll prepare / I’ll get ready

With 〜ておきます, the speaker sounds more intentional:
I’m doing this now so things will be ready later.

Because this is a grammatical construction:

• する in て-form → して
• plus おく
• polite present/future form of おく → おきます

So:

• する
• して
• しておく
• しておきます

This is normal Japanese grammar. It is not one dictionary verb; it is a combination:

[verb in て-form] + おく

In casual speech, people often contract it:

• しておきます → しときます
• しておく → しとく

But in careful or standard written Japanese, しておきます is the safer form.

Because Japanese often leaves out the subject when it is understood from context.

So even though English usually wants:

• I’ll get ready early for tomorrow’s trip

Japanese can simply say:

• 明日の旅行の支度を早めにしておきます。

The subject might be:

• I
• we
• sometimes even someone else

But in most everyday contexts, listeners can tell from the situation.

This is very normal in Japanese. If the speaker wanted to emphasize the subject, they could say:

• 私は明日の旅行の支度を早めにしておきます。

But usually that is unnecessary.

Japanese 〜ます forms do not work exactly like English present tense.

おきます can mean:

• do / do habitually
• will do
• sometimes even a planned future action

In this sentence, because of 明日 and the overall context, it is understood as a future or intended action:

• I’ll get ready early
• I’m going to prepare early

So even though the form is おきます, the meaning here is future-oriented.

It is broader than just packing.

旅行の支度 can include:

• packing your bag
• getting clothes ready
• charging devices
• arranging tickets/documents
• setting things up before leaving

Depending on context, English might translate it as:

• pack
• get ready
• prepare for the trip
• make preparations for the trip

So if the situation is clearly about luggage, pack early may be a very natural translation. But the Japanese itself is not limited only to packing.

Yes. A few close alternatives are:

• 明日の旅行の支度を早めにします。
• 明日の旅行の支度は早めにしておきます。
• 明日の旅行の準備を早めにしておきます。

Nuance differences:

• 支度を早めにします
  Simpler: I’ll do the preparations early.

• 支度は早めにしておきます
  Adding は puts focus on as for the preparations, I’ll do those early.

• 準備 instead of 支度
  Slightly more general/neutral than 支度

The original sentence with 〜ておきます strongly suggests doing it ahead of time on purpose, which is why it sounds very natural.