Having done some long runs in the Presidential range of the White Mountains I am pretty familiar with the rocky nature and the steepness of the trails. If you are planning to cover this much terrain in under 24 hours I suspect you will need to be running a good bit of it. That is exactly what this training plan is geared towards. Ultra runners on very hilly courses normally walk the steep hills as well. This plan is progressive in that it builds from 25 mile weeks to finally hitting 50 miles in the biggest week. Consistency and building of that time on your feet is going to key to the success of this or any other training program.
I hope this helps.