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This is an excellent idea. Living alone can help create an "echo chamber" (for lack of a better term) for negative emotions. Dogs (especially trained companion dogs) almost never contribute to these negative emotions. Having someone/something to care for and who depends on you is sometimes a substantial boost to one's psyche.
Yes. I suffered from clinical depression years ago, and the number one thing that stopped me from ever harming myself was knowing that my cat was completely dependent on me. Even if I had arranged matters so I knew I would be found before she could starve or anything, I knew she wouldn't understand why I was gone. Those thoughts always triggered a huge sobbing jag, but they kept me alive.
The traveling thing - it's funny you should mention that. A month ago I did exactly this. I've left my business running and I've gone to another country. I am trying to spend as much time as possible volunteering, to help other people, as I thought this might help me. So far unfortunately I have felt very bad here. I am not entirely sure why. I will be here for another 2 months before I return.