The ODP doesnt take that much planning. You have the guide books so just do it. Accomodation is easy enough to find as its not all that a busy route and I think you could even go on spec without dificulty. The only thing is, do not under estimate the walk. The fact that there is over 20,000ft of ascent and descent, and many, many high stiles to negotiate, makes it a harder walk than the Penine way. It may be a third shorter in distance but the average daily climbing is more, as its done in half the time.