My first thought was "gee, so many questions!". lol
Since you aren't looking for answers to them all, I'll answer.
I have been in med-surg nursing for 16 years. 15 of those at the same hospital where I've worked in neuro, telemetry, and now trauma med-surg. I've worked night shift for 13 years and day shift for the rest. Day shift is better for my tired old body. I've worked 12 hour shifts, but am currently working Mon-Fri 8-hour shifts. There are advantages and disadvantages to all shifts, schedules, and lengths of shifts. The trick is to find one that works best for you. It takes me about 7 minutes door to door to get to work.
Who is ever happy with the money they make???? However, basically, yes, I'm happy. My salary started at 12/hr and is up to $31.00 hour so I can't complain.