Advice anyone?

I wouldn't resign my current job until I had a definite committment from the new job -- but once you get that, then I would recommend going there if you truly feel it is a better work environment.

As for level III or level II ... You have to be very honest with yourself, here. You say in your post that you feel you need more support from your coworkers in your current level III situation. While some of that feeling may indeed due to working with some unsupportive individuals, some of that feeling might be coming from a disccomfort with the level of acuity. If you feel that is a significant aspect of your current feelings of insecurity and discontent, then I would recommend switching to the level II section. Then, after a year of two of intermediate care, you will have more confidence in your skills and be familiar with the hospital's usual procedures. You can then switch to the level III when you feel ready to do so. If you have been a good level II nurse, your employer should be happy to have you switch to level III when you feel ready.

If on the other hand, you feel confident in your level III readiness and believe it is just the personalities you are working with that is causing you a problem now ... and if the new hospital will give you the orientation and long-term support you will need ... then there is nothing wrong with choosing the level III option now. Just be sure that you will get a good orientation and that the culture is truly more supportive than the one you are leaving before you switch. You could be "jumping from the frying pan and into the fire." Don't assume that the grass is greener elsewhere: thoroughly check it out. If you have any doubts, start with the level II care and see how things develop.