I also want to add that the exam is quite expensive to take--$295 for an HPNA member and $415 for a non-member...
--but if you wait until you are employed in hospice, your employer will usually reimburse you after you pass.
I didn't want to discourage you, and I hope you have a long and fulfilling career in hospice. I just wanted to be honest about what to expect. I am just now going back to hospice after being a dialysis nurse for two years, and when I told one of my co-workers in dialysis that I was a certified hospice nurse and that the exam was really hard, he smirked and said, "Oh, yeah, I'll bet it was!" in a very sarcastic tone. I don't know why people assume that hospice is easy or that any certification exam would be easy. I know you don't, I'm just saying that a lot of people have the mistaken perception that hospice nursing is easy and that there's not much to know about end of life care. It's a specialty, just like any other type of nursing.
I also think someone who's been an RN for 20+ years with private duty experience would have no trouble finding a hospice position. Start applying and I bet you'll get calls for interviews, no problem. Already being experienced in working in the field is a big plus.
I wish you all the best!