Me encanta que mi hermana conduzca hasta la playa y vuelva temprano.

Because encantar works like gustar.

• me = to me
• encanta = is delightful / delights

So the structure is not I love X in a literal word-for-word way. It is more like X delights me.

In this sentence, the subject of encanta is the whole clause que mi hermana conduzca hasta la playa y vuelva temprano, so encanta stays in the third person singular.

After verbs and expressions of emotion, reaction, or evaluation, Spanish normally uses que to introduce the next clause.

So:

• Me encanta que...
• Me molesta que...
• Me alegra que...

In English, that is often omitted, but in Spanish que is normally required here.

Because me encanta que... triggers the subjunctive.

Spanish uses the subjunctive after expressions of emotion when you are reacting to someone else’s action:

• Me encanta que mi hermana conduzca...
• Me alegra que vengas
• Me molesta que hablen tanto

The idea is not that the action is unreal. It is that the main clause expresses a feeling about it, and that is a very common environment for the subjunctive.

Not with this meaning.

If the subject of both parts is the same, Spanish often uses the infinitive:

• Me encanta conducir hasta la playa y volver temprano
  = I love driving to the beach and coming back early.

But in your sentence, the person who feels the emotion is me, and the person doing the actions is mi hermana. Since the subjects are different, Spanish uses que + subjunctive:

• Me encanta que mi hermana conduzca...

They are present subjunctive forms.

conduzca

From the verb conducir:

1. Present yo form: conduzco
2. Remove the -o
3. Add subjunctive endings

So:

• conduzca
• conduzcas
• conduzca
• conduzcamos
• conduzcáis
• conduzcan

vuelva

From the verb volver:

1. Present yo form: vuelvo
2. Remove the -o
3. Add subjunctive endings

So:

• vuelva
• vuelvas
• vuelva
• volvamos
• volváis
• vuelvan

Notice that volver is a stem-changing verb, so o → ue in most forms.

Because conduzca and vuelva have the same subject: mi hermana.

Spanish does not need to repeat the subject if it is still clear:

• que mi hermana conduzca hasta la playa y vuelva temprano

This is the normal, natural version.

You could repeat the subject for emphasis, but it would usually sound heavier and less natural.

Yes, it is possible, but it is not the most neutral version here.

• Me encanta que mi hermana conduzca hasta la playa y vuelva temprano
  = the smooth, standard way

• Me encanta que mi hermana conduzca hasta la playa y que vuelva temprano
  = also grammatical, but it gives a little more separation or emphasis to the second action

If both actions belong to the same person and the same idea, Spanish often prefers the shorter version without repeating que.

Here hasta means to / as far as / all the way to.

So conduzca hasta la playa means that she drives all the way to the beach.

This is very natural with conducir. It avoids possible ambiguity, because conducir a can also mean to lead to or to result in, not only to drive to.

Because temprano is an adverb here, not an adjective.

It modifies the verb vuelva:

• vuelva temprano = comes back early / returns early

Adverbs do not change for gender or number, so it stays temprano.

Yes. In Spain, conducir is a very standard and natural verb for to drive.

You will also hear manejar in some places in the Spanish-speaking world, especially in Latin America, but conducir is especially normal in Spain.

So this sentence sounds very natural for Spain Spanish.

Because Spanish treats the whole que clause as one single idea:

• que mi hermana conduzca hasta la playa y vuelva temprano

That whole clause is the thing that encanta you.

So the verb stays singular:

• Me encanta que...

If the subject were clearly plural nouns, then you would use encantan:

• Me encantan los libros y las películas