sakamiti no yuuhodou wo aruku.

A natural reading is:

• 坂道 = さかみち
• の = の
• 遊歩道 = ゆうほどう
• を = を (pronounced お in modern Japanese)
• 歩く = あるく

So the whole sentence is read:

さかみち の ゆうほどう を あるく。

の connects two nouns.

Here, it links:

• 坂道 = slope / uphill road / hill road
• 遊歩道 = promenade / walkway / pedestrian path

So 坂道の遊歩道 means something like:

• the promenade on a slope
• the walkway of a sloping road
• the sloped promenade

In Japanese, A の B often means B related to A. The exact relationship depends on context.

Yes, 歩く is usually intransitive, but を is still often used to mark the place or route that someone moves through.

So in this sentence, 遊歩道を歩く means:

• walk along the promenade
• walk on the promenade
• walk through the promenade area

This is a very common pattern in Japanese:

• 道を歩く = walk on/along the road
• 公園を散歩する = take a walk in the park
• 橋を渡る = cross the bridge

Here, を does not mean a direct object in quite the same way as English.

The structure is:

• 坂道の遊歩道 = the sloped promenade / the promenade on a slope
• を = marks the route/place being traversed
• 歩く = walk

So the pattern is:

[place/route] を [movement verb]

And more generally:

[noun modifier] + [noun] + を + verb

Japanese puts the verb at the end, which is normal.

Japanese often omits the subject when it is already understood from context.

So 坂道の遊歩道を歩く。 could mean:

• I walk along the sloped promenade.
• He walks along the sloped promenade.
• They will walk along the sloped promenade.

The subject is simply not stated here. That is very natural in Japanese.

歩く is the plain, non-past form.

That means it can express:

• a present/habitual action: walk / walks
• a future action: will walk

Which one it means depends on context.

For example:

• 毎朝、坂道の遊歩道を歩く。 = I walk along the sloped promenade every morning.
• 明日、坂道の遊歩道を歩く。 = I will walk along the sloped promenade tomorrow.

Grammatically, it works as one noun phrase.

The main noun is 遊歩道.
坂道の describes it.

So the focus is on the promenade/walkway, and 坂道 gives extra information about what kind of promenade it is.

You can think of it as:

• a promenade related to a slope
• a promenade on a hill
• a sloping walkway

Yes. In normal Japanese, it would usually be written as:

坂道の遊歩道を歩く。

The spaces in your example are only there to make it easier for learners to see the parts.

Japanese normally does not use spaces between words.

遊歩道 usually means a pedestrian walkway, promenade, or walking path. It often suggests a path meant for walking in a pleasant or scenic way, not just an ordinary road.

So compared with:

• 道 = road / path
• 坂道 = sloping road
• 遊歩道 = promenade / walking path

遊歩道 sounds more like a designated walking route.

Yes, but it means something slightly different.

• 坂道を歩く = walk on/along a slope or uphill road
• 坂道の遊歩道を歩く = walk on the promenade that is on a slope / the sloped promenade

So the longer version is more specific. It tells you that the place is not just any slope, but specifically a 遊歩道.

Yes, it can be a complete sentence, especially in notes, captions, diary-style writing, or simple descriptive text.

However, in real conversation, Japanese often includes more context, such as:

• 坂道の遊歩道を歩く。気持ちいい。
• 朝、坂道の遊歩道を歩く。
• 私は坂道の遊歩道を歩く。

So the sentence is grammatically complete, but it may feel a little context-light on its own, just like Walk along the sloped promenade or Walking on the sloped promenade can feel brief in English.