Requirements in our area are pretty simple. BLS experience of at least one year in the field, currently belong in a system as a basic, no pending disciplinary actions, good recommendations. Then you have to knock off the anatomy and physiology requirement but that can be done concurrently with the Intermediate level classes.
What to expect - hard work, lots of studying, many hours of clinicals in hospital rotations, many hours of clinicals in the back of a truck, and like many of us who worked full time while in the P program - not much of a personal life. But it's a great learning experience and a great satisfaction of accomplishment.