Renal floor to ICU; getting your foot in the door?

I applied to the renal floor of a large hospital (one of those areas that always seems to have a spot available) and think they will call me back for a second interview. I'm really interested in working ICU. Am I thinking on the right track when I assume I will be able to get into certain positions in the hospital easier when I get my foot in the door by getting hired on? Will they hire from within the hospital first?

Also, you think I can work three 12's a week and go to FNP school, too?