Not sure how much help I can be since I'm not a nurse (yet), but I spent a few years as an officer and worked closely with the nursing staff. A good start is to search the forum as well, as some of your questions may already be answered.
To make it simple, here's some pros/cons that I can think of.
Pros- Steady job, fairly regular routines (as many of your patients will probably be on a much longer term basis than would be at a hospital), and a good starting point for resume building. That's about it...
Cons- Biggest issue is that it is a very stressful job. You are not only expected to follow policies/procedures of the nursing staff which is often contracted, but you must follow those of the prison/security as well. There are also federal laws that might apply differently in a prison setting than a hospital. You are constantly under pressure by prison schedules, dealing with a lot of 'difficult' inmates, and charting/pill call/emergencies/whatever else you can think of for several hundred or more (Leavenworth has about 1,800) offenders. Often times the nursing staff is on a different rotational work schedule than security which can make things more difficult.
Also, working in a very predominately male environment leads to other issues. A prison sort of operates as its own little world, and gossip for males working there can be just as bad or worse than anywhere else outside the fence. Not to mention as being some of the few female staff, you'd most likely have males (both officers and offenders) fawning over you and seemingly tripping over each other in an effort to flirt with you. In my experience, this tends to be quite detrimental to the safety and security of the institution and in most circumstances, at no fault of the women.
That leads me to what advice I feel I should give if you do decide to choose to go into correctional nursing.
While these things may not apply to every single person, it does for most inmates, therefore you must apply this mindset to ALL of them. They are VERY manipulative and lie frequently. The basic rules apply to both security and nursing staff when dealing with offenders. Be firm, fair, and consistent. I do not care how nice and personable they seem to be, for your sake and everyone else's be vigilant and do not ever ever EVER trust them! I absolutely cannot emphasize that enough.
I know though both personal experience and know way too many staff that fall for this. It doesn't matter if the staff is male/female, officer, case worker, nurse, whatever. My own wake up call was early on when a little old diabetic man with a cane that I escorted to medical everyday once kicked off his flip-flops and RAN down the wing and began punching another inmate in the back of the head. It took me completely off-guard and for a brief second I stood there dumbfounded, thinking "He can run?" Do not become complacent and assume what they can/cannot be capable of or how they might behave or react in situations.
Again, these guys can be very manipulative. I have known several staff that have brought in drugs/contraband for or developed relationships with inmates. We had one case worker quit and when the guy was paroled, she was at the front door to pick him up! We had an officer bringing in contraband and when she was fired, her mother (in charge of laundry) brought it in for her. After the inmate's sentence was up, he moved in with the former officer.
Inmates will cheek pills, sell pills, simply not take them, fake some injury or illness, insist they need a bottom bunk or extra blankets, lie about how they got their face busted up ("I fell in the shower." "I fell into my locker." "I fell on the stairs." are some common excuses when they get into a fight and don't want to be labeled a 'rat' by other inmates), among other things.
As I said before be firm, fair, and consistent. Stay on your guard and be polite and professional. A smile on your face is not a bad thing and there is nothing wrong being nice. They should know by our actions that we realize they are human and it isn't our place to judge them, but there is a fine line to walk and for safety's sake- please do not trust them.