In my opinion, I think option 2 might be best. I mean double majoring in neurobiology and psychology would be phenomenal for your med school applications and you have an opportunity to spread it out to make it easier on you. Plus, if you do feel like you will be depressed sometime in the future, it seems best to stay in a familiar place to receive help.
Doing the 4 years doesn't mean you have to lose the opportunity to travel. A lot of my friends in the med track usually take off a year after 4 years of undergrad.
The 3 year plan would help you finish things faster and give you the opportunity to travel, like you want. But the only problem is if you need somewhere to cope, going to an unfamiliar location might not be best, and if you lose interest in travel, that will just make things worse. If you can arrange for a support system abroad or somewhere to cope, it would make things better.
But I would go with the 4 year option.
I wish you all the best Secretum