@SeattleWoman I just finished the Norte relying on my phone alone. I had two apps:
1) Wise Pilgrim, which gave me a text description of the upcoming day's walk, and a different (broader) list of accommodations
2) Buen Camino, which allowed me to plan and track stages, as well as both online and offline maps. I used it heavily when in cities or trying to find an alternate route / alternate accommodations.
The advantages: less weight. Two apps, one with the same content as the book, the other with a GPS that didn't require wifi/cell data. Both up to date on the accommodation side, and really easy to navigate. Both had elevation profile and distance calculators. When I did want to make a same-day reservation (not too often, don't worry), I just had to click on the phone number. The Buen Camino app and stages planning was especially useful on the Norte because some days could be especially long and difficult. I could plan and tweak as I went along.
The disadvantages: My cell phone died repeatedly along the way. It turns out there is a little glitch that if I didn't pay attention to my camera settings, I'd chew through battery in an hour. I got stuck without a guide a couple of times. Was this an issue? Nope, not really. I got lost the first day out, and learned that if you don't see an arrow where you expect one, you've gone the wrong way. Go back to the last one you saw and start over. Also, the locals are really nice and will help a pilgrim as best they can. I realized I didn't need to worry too much along the way (and the maps in the guidebooks wouldn't have been that helpful when wondering where I was anyways).
The one thing I did miss when my phone went out of commission, was knowing how much further to the next bar/restaurant/albergue, particularly when I was tired. It made it feel soooo much longer when I didn't know. But then, I also remember a day I was compulsively checking my phone for progress, and the dismay when I realized just how slow I was walking. So, maybe not so much of a disadvantage.
Finally, I met a few people that didn't have a guide book at all! They did some research before hand, but really wanted to be open to whatever experience came their way, and didn't want to regret the things that they missed. In retrospect, this is not a bad thing either. Just depends on the comfort level of the pilgrim.
Before I walked, I read all kinds of guides and memoirs, mostly purchased through Kobo, several of which were self-published. They were delightful, and helped figure out where to spend time on preparing, but without being a "guide book" per se. "What the Psychic Told the Pilgrim" and "Slacker Pilgrim" were two favorites. I also read "Te Art of Pilgrimage: The Seekers Guide to Making Travel Sacred" by Phil Cousineau. This was an invaluable help with the spiritual and mental preparation - I am sad I didn't discover it earlier, because it added to my reading list, which in turn added to the richness of my pilgrimage. If I'd had more time, I would have read more about Santiago de Compostella.
Listening to stories, and hearing from other people is a really great way to help figure out what to focus on. And pick up little, helpful tips like how to order food in a bar. Seriously. Very helpful advice. Several people mentioned local camino groups in your area - if you can, meet up with them. I promise you, it is worth it!