I was actually a bounty hunter for a while. I once had to go into Mexico after some guy. I was a bartender for years, and for about 6-8 months I worked in corrections. I never wrote about those stories though. I think that everything you need is there already.
Imagination is everything.
If you've been beat up once in your school yard, it's not that hard a stretch to imagine getting knifed in prison. For the last 10 years I've worked mostly as a college teacher and a carpenter. My car was the quietest place I could find to write. I write in longhand with a pencil anyway. I'd pull over in the mornings and work on my book.