Learn Dutch: De planning was inmiddels vol, vandaar dat we laat zouden weggaan. - The schedule was full by now, hence we would leave late.

De planning was inmiddels vol, vandaar dat we laat zouden weggaan.

The schedule was full by now, hence we would leave late.

Breakdown of De planning was inmiddels vol, vandaar dat we laat zouden weggaan.

Questions & Answers about De planning was inmiddels vol, vandaar dat we laat zouden weggaan.

Why do we use zouden weggaan here instead of just the past tense gingen weg?

This sentence uses the "future in the past." The first half is set in the past (was), and the leaving was a future plan from that past perspective. Just like in English ("we would leave late"), Dutch uses zouden plus the infinitive to show a future intention seen from the past.

Could I use daarom instead of vandaar dat to say "hence" or "that's why"?

You can, but it changes the word order. The word dat in vandaar dat forces a subordinate clause, pushing the verbs to the end (dat we laat zouden weggaan). If you use daarom, it triggers inversion because it is an adverb: daarom zouden we laat weggaan.

Why are both verbs (zouden and weggaan) placed together at the very end of the sentence?

This is the standard rule for subordinate clauses in Dutch. Because the clause is introduced by dat, all verbs in that clause are kicked to the end.

Is inmiddels the same as ondertussen?

Yes, for a B1 learner they are practically exact synonyms. Both mean "meanwhile" or "by now" and indicate that something has changed or happened in the time leading up to this moment.