Removed from the world. Seclusion. The cell being the hermitage. Like the cell of a monk. This I would call "favorable conditions".
We all are prisoners. Some know, some don't and some just can't escape experiencing it directly.
Sorry, but prison is never a favorable condition. Unless you are in solitary, you are not secluded. And most other inmates, are not conducive to good spiritual growth.
That depends on how you are looking at it. Never say "never".
("Inner" and "outer") obstacles are the path, the path is ("inner" and "outer") obstacles and not being able to escape these obstacles by means of common distractions may be very conducive.