If you do a quick search on the Interwebz, you'll find a tremendous number of ultramarathon training tips and advice. You'll find dozens of training plans, philosophies, techniques, and research. You'll also find a ton of information refuting each and every one of those training plans, philosophies, techniques, and research.
What does this mean?
There is no one right answer.
You can follow a lot of different plans and still get to the finish line. You can even make up your own plan out of thin air. It does help to have some guidance, though, so how do you choose? Many are tempted to just do what their favorite elite runner does. This will probably work, but that elite, like every other runner, is a different individual. Their plan probably isn't the best fit for you.
I'll discuss a large number of ideas to consider from training plans to the tiny details of ultrarunning. I would highly recommend developing your own process of experimentation to decide how to deal with each issue. Test out a wide variety of ideas. Keep those that work. Get id of those that do not. By using this process, you will continually improve using the methods that work best for you.
In essence, think of your ultramarathon training as one huge experiment, and you're the subject.
Here's the method:
Step One: Choose the new thing to test. It may be a food, piece of gear, exercise, what lube prevents your junk from chafing... whatever. Only change one variable at a time.
Step Two: Test the new variable. In many cases, this will involve going for a run. Pay close attention to the effects of the variable. If it is a food, how did it make you feel? Was it easy to eat? Is it something that can be carried with you?
Step Three: Decide if the variable helped, hurt, or further experimentation is needed. If it seemed to help, adopt it as part of the training. If it hurt, abandon it. If further testing is needed, try it again.
This simple process can be used to tailor you training to YOU.