Hi TD,
I am currently in a blended program. I take courses online, and then attend a 3 day seminar each trimester. There are several types of DNP programs. Not all of them lead to nurse practitioner, many are set up as post-masters programs. If you are looking for a "totally online" program because you can not spare 3 or 4 days out of your schedule you will not be happy with an online program. Online learning takes much more time than attending courses on campus. If you are looking for online because you are homebound or otherwise unable to travel but you have time to study, then online is a good option. Studying for online programs, as I stated above, is VERY time consuming. I would not recommend enrolling full time in a program (9 credits or more) if you intend to keep working. The curriculum is very demanding, and requires many hours of research.
If you post a little more information about what you intend to gain from a DNP program, you may get more personalized useful information. i.e. do you want to be a nurse anesthetist, a nurse practitioner, a hospital administrator, an university professor? It is also helpful to know what part of the country you are in, and why you feel you could not travel somewhere for a few days a few times a year.
http://www.tu.edu for information abou the program I am in. I am enjoying my education, but it it hard...Doctorate programs are like that!