På vägen hem sa mormor att nästa picknick gärna får vara vid havet i stället.

This is a fronted time/place expression, meaning something like on the way home. Swedish often puts this kind of information first to set the scene.

Because something other than the subject comes first, the finite verb must still stay in second position. That is why you get:

På vägen hem sa mormor ...

and not På vägen hem mormor sa ...

This is a very common Swedish word order pattern.

Hem usually expresses direction: homeward / to home / home.

Hemma usually expresses location: at home.

So:

• på vägen hem = on the way home
• hemma = at home

Compare:

• Vi gick hem. = We went home.
• Vi var hemma. = We were at home.

Swedish follows the V2 rule in main clauses: the finite verb normally comes in the second position.

Here, På vägen hem takes the first position, so the verb sa must come second, and the subject mormor comes after it:

• På vägen hem = position 1
• sa = position 2
• mormor = subject after the verb

If the subject came first, then you would say:

Mormor sa på vägen hem ...

Both are possible, but they emphasize things slightly differently.

Att introduces a subordinate clause, like that in English:

mormor sa att ... = grandmother said that ...

In English, that is often optional. In Swedish, att is very commonly used in this kind of sentence.

The clause after att is:

nästa picknick gärna får vara vid havet i stället

That whole part is what she said.

In Swedish, words like nästa, första, sista, and similar determiner-like words often make an extra article unnecessary.

So:

• nästa picknick = the next picnic
• not usually den nästa picknicken in this context

This is normal Swedish structure.

Compare:

• förra veckan = last week
• nästa gång = next time
• sista dagen = the last day

That is a very good question. Gärna often does mean gladly, but in many sentences it is used more idiomatically.

Here, gärna får vara softens the statement and gives it the sense of a preference or suggestion:

• nästa picknick får gärna vara vid havet ≈ the next picnic can preferably be by the sea
• or more naturally: I’d be happy if the next picnic were by the sea
• or: The next picnic should preferably be by the sea

So gärna adds a polite, wish-like tone rather than a blunt command.

Literally, får can mean gets to, may, or is allowed to. But in this pattern, får gärna + infinitive is a common idiomatic way to express a polite wish or recommendation.

So:

• Det får gärna vara varmt i morgon. = I hope it will be warm tomorrow.
• Du får gärna ringa. = Feel free to call.
• Nästa picknick får gärna vara vid havet. = The next picnic can preferably be by the sea / I’d like the next picnic to be by the sea.

So yes, the literal idea is something like may be, but the real meaning is softer and more natural than gets to be.

Swedish usually uses the definite form here: havet = the sea.

In many contexts, Swedish uses the definite form where English might say the sea in a more general sense:

• vid havet = by the sea
• på landet = in the countryside
• i skogen = in the forest

So vid havet sounds natural and idiomatic.

They mean different things:

• vid havet = by the sea, near the sea, at the seaside
• på havet = on the sea, out at sea

For a picnic, vid havet makes sense because you are near the sea, not floating on it.

I stället means instead.

It signals a contrast with some other place that had been discussed or implied. So the grandmother is suggesting a different location from the previous one.

Placing i stället at the end is very natural in Swedish. It often comes late in the sentence when it comments on the whole idea:

nästa picknick gärna får vara vid havet i stället

That sounds smooth and idiomatic.

Swedish often uses family words like names when the reference is clear, especially in narration:

• mamma
• pappa
• mormor
• morfar

So sa mormor can sound like grandma said in a story, where the person is already understood.

If you said min mormor, it would sound more explicitly like my grandmother, which is also possible, but less natural in many story-like contexts.

Yes, but its position affects the feel slightly. In this sentence, gärna is placed before får in the subordinate clause:

att nästa picknick gärna får vara vid havet i stället

That is a natural placement.

You may also see får gärna together very often:

• Nästa picknick får gärna vara vid havet.

In practice, learners should remember the chunk får gärna because it is extremely common and useful.

Swedish often uses the present tense to talk about the future when the context already makes the future meaning clear.

Here, nästa picknick already tells you this is about a future event, so får vara is completely natural.

This is similar to English sentences like:

• We leave tomorrow.
• The next meeting is on Tuesday.

So Swedish does not need a special future form here.