I normally try and do "fun" work. This largely depends on how autonomous your job is. I was a PhD student doing research for a company and I received very little oversight for 3 years.
The supervision I did receive was great though. They understood needing to take a break and slow down. At those point I would generally read papers, watch PyData talks (highly recommend them, like inspirational ted talks for data people), or contribute to open source to learn about new tools or design paradigms.
Depending on what config data you need it might be a good idea to use environment variables. If all you need are server locations and credentials then environment variables are likely your best bet.
If you need fancy JSON or something else, global variables are nice.