Lad os gå til museet til fods i stedet for at tage bussen.

In Danish, Lad os literally means let us, and it is the normal way to say let's in English.

• Lad = imperative of lade (to let)
• os = us

So:

• Lad os gå = Let's go
• Lad os spise = Let's eat

This is very close to older or more formal English let us, but in modern English we usually contract it to let's.

Because after Lad os, Danish uses the infinitive form of the verb.

• gå = infinitive, to go / go
• går = present tense, go / is going

So:

• Lad os gå = Let's go
• not Lad os går

This is similar to English:

• Let's go
• not Let's goes

Til usually means to or toward, and museet means the museum.

So:

• til museet = to the museum

Here, til shows direction or destination.

Also note the noun form:

• et museum = a museum
• museet = the museum

Danish usually puts the at the end of the noun as a suffix, rather than as a separate word.

They are two different fixed uses of til.

1. til museet
   Here til means to in the sense of destination:

   • gå til museet = go to the museum

2. til fods
   This is a fixed expression meaning on foot:

   • til fods = on foot

So even though the same word appears twice, it is doing two different jobs.

It is simply the standard idiomatic expression.

• til fods = on foot
• literally it relates to foot/feet, but you should learn it as a set phrase

Examples:

• Vi går til fods. = We're going on foot.
• Han kom til fods. = He came on foot.

English uses on foot, while Danish uses til fods. This is just one of those language-specific expressions.

I stedet for means instead of.

It is a very common Danish expression.

Examples:

• te i stedet for kaffe = tea instead of coffee
• bliv hjemme i stedet for at gå ud = stay home instead of going out

In your sentence:

• i stedet for at tage bussen = instead of taking the bus

Because when i stedet for is followed by a verb, Danish normally uses at + infinitive.

So:

• i stedet for kaffe = instead of coffee
  because a noun follows

but:

• i stedet for at tage bussen = instead of taking the bus
  because a verb follows

Here:

• tage = infinitive to take
• at tage = to take

English often uses -ing after instead of, but Danish usually uses at + infinitive in this structure.

Yes. Danish commonly uses tage (take) with transport, just like English often does.

• tage bussen = take the bus
• tage toget = take the train
• tage metroen = take the metro

You may also hear other expressions in Danish, such as:

• køre med bussen = go/travel by bus / ride the bus

But in this sentence, tage bussen is the most natural equivalent of take the bus.

Because the sentence is referring to the museum and the bus, not just any museum or any bus.

Danish marks definiteness mainly by adding an ending to the noun:

• et museum = a museum

• museet = the museum

• en bus = a bus
• bussen = the bus

This is one of the biggest differences from English. Instead of putting the in front, Danish often attaches it to the noun.

It depends on the noun's grammatical gender.

• en-word nouns usually take -en in the singular definite
• et-word nouns usually take -et in the singular definite

So:

• en bus → bussen
• et museum → museet

This is why the sentence has both endings: the two nouns belong to different genders.

Yes, that is possible, but it means something slightly different in structure.

• Lad os gå til museet til fods focuses on walking
• Lad os tage til museet til fods sounds more like let's go/get to the museum on foot

The original sentence is very natural because gå and til fods fit together well. Since til fods already implies walking, gå makes the meaning very clear and idiomatic.

The sentence breaks down like this:

• Lad os gå = Let's go / Let's walk
• til museet = to the museum
• til fods = on foot
• i stedet for = instead of
• at tage bussen = taking the bus / to take the bus

So the pattern is roughly:

Lad os + infinitive + destination + manner + i stedet for + at + infinitive

A very literal breakdown would be:

Let us go to the museum on foot instead of to take the bus

But natural English says:

Let's walk to the museum instead of taking the bus.

Yes, it is completely natural.

A Danish speaker might also say similar variations, for example:

• Lad os gå til museet i stedet for at tage bussen.
  = Let's walk to the museum instead of taking the bus.

• Lad os tage til museet til fods i stedet for at tage bussen.
  = Let's go to the museum on foot instead of taking the bus.

• Lad os gå derhen i stedet for at tage bussen.
  = Let's walk there instead of taking the bus.

Your original sentence is idiomatic and clear.