I can't answer all of your questions...I share a few of them myself! I have been toying with the idea of going back to work since I've had a baby. I have worked in cardiac step-down as well. I'm not quite sure what the lingo is out here in CO, since I haven't worked here yet
I have a friend that works at U of Colorado Hospital in Denver. She is working in the cardiac unit, and participated in an internship right after she was hired. She did sign something that said she had to work there for a minimum of 2 years. I have no idea how much she makes, though.
In my web surfing for jobs, I have found that Exempla Good Samaritan Hospital in Lafayette, CO has a critical care internship. http://www.exemplajobs.org/
has more info and contact persons.
As for wages, I checked out www.salary.com
I actually have an interview next week at a hospital in Boulder, and I'm trying to decide how much to ask for wages!
Good luck to you