Translation:I want to travel and relax a bit.
It does and it is counter-educational. You get marked wrong because the course is half baked.
Here they want the answer: "I want to travel and relax a bit" But the first part is 我想去旅游 ie: I would like to go travelling.
So in English we would more likely say "I want to go travelling and relax a bit". Which is what the Chinese says anyway.
You have two clauses in the one sentence, so in English you need a conjunction (such as AND) between them, not a comma. Alternatively you could place the clauses in separate sentences and provide a subject for the verb in the second sentence. Although just using the comma to link the clauses is OK in Mandarin, Duo has inserted the conjunction AND to make the sentence grammatically correct in English.
Looked up Xiu xi 休息 vs qing song 轻松 cause I'm more used to the former than the latter
Xiu xi 休息 is a rest after some hard exercise or work as in a break
Qing song 轻松 is relaxation by taking things lightly such as in a vacation
Interestingly Qing song (same tone but different Qing character青松 ) is also a pine tree.
As for the clamour over the translation:
I deal with the block choices Duo gives me, so my suggestion to repair this is very simple:
Add the '...to go traveling...' but accept it as "....to travel...." as well
Add the 'and' but accept the answer without it as well (maybe use a dash instead of a comma in the translation)