That depends on where on the Timeline those days would be, so I chose 10 in Mustafar Pre Imperial Era

but if it was right after Revenge of The Sith, I would either go to Dagobah or Dathomir, because there would be trusted people like Master Yoda and Merrin

^any era, that fits best for you

Dathomir for me, it's easily the most urbanized out of the four

Dathomir! I could learn magic, and hang out with Merrin, and get a cool energy weapon, It'd be fun!

The nightsisters are kinda hot so Dathomir

I personally would spend 20 days on Dagobah

Definitely Dathomir. It has the most pleasant climate, and the locals are friendly ever since the Zsinj campaign.

I could probably make friends with the Nightsisters, and they would help me survive. Plus, it would be great to get to know them better! So I would go to Dathomir for 15 days (or maybe more if I really liked it, lol.)

Mustafar is actually my favourite planet is the franchise, no way I'm gonna pass my opportunity to go to mustafar

Mustafar is to hot and you would probably die quickly.

Dathomir is if hell was a planet so definitly not.

Dagobah only is a swamp which Yoda was able to live in for like 20 years or so and the only thing really bad there is the large dark side present.

And geonosis is just lame it has a bunch of bug guys on it EWW.