I hope not very hard.. I haven't applied to any and don't really plan to. It's just more time and money that I don't have. I'm hope I can stay at my own program without much problem.
Difficulty is determined by location and quality of prog. If it is a great program and/or location, better chance that it WILL fill. There are always exceptions. I think you will very easily scramble into a PGY-1 prog of some variety, somewhere but you may have to move to your gas spot after a year.