c# Best way to access multiple databases

I am creating a c# executable to run as a scheduled task. The .exe is going to access multiple databases and update the same table and columns on each. The databases are split up by location. What is the best way to access multiple databases? Should I:

• Put the connections in the app.config and maybe use Entity Framework to access each database?
• Put the connection information in a .txt file and then use the SQL library to open connection, make update, close connection?