I walked 200 miles on the Camino in 2002, so I guess that makes me an expert. ;-)
I suggest that you plan no more than 20 km per day, average. If you are 60 something I would cut that back to 15 km. You are talking well over a month. 750 km divided by 15 km/day is 50 days.
I don't suggest that you depend on divine providence for meals or a place to stay, to me that is freeloading. You will find on pilgrimage that you will need help at different times, and there is where the divine providence comes in. Meals and a place to stay are not expensive, I would figure 25 euros a day.
Amazingly, I never got one bad direction from anyone while I was on Camino. Ask for directions. Occasionally someone would say that they did not know, and occasionally someone would tell me without my asking that I was going the wrong way. ;-)
You have probably heard the joke where a man prays every day to win the Lottery. One day he has lost patience and cries out more than usual, "Why haven't you helped me Lord"? The Lord answers him, "Couldn't you at least buy a ticket?" Applying that to this case, you need to do as much as you can to be ready and to use good judgement on the trip.
While the movie the Way was Hollywood drama, there is a lot of truth in it. The dorms really do look like in the movie, at least some of them. You will also tend to keep running into the same people over and over, and some of them become your trip companions. Most people are not walking for religious reasons, but some are for vaguely spiritual reasons.
Obviously good hiking boots and a light pack are key. Getting in shape is also important, of course. If your pack is over 20 pounds you need to look harder at it and take some things out. No need for a tent or cooking gear.
I have mixed feelings about taking a phone or a smartphone. Part of going on pilgrimage is disconnecting from your regular life. But family and others will want to know how you are doing. I sent out an email to a list of people every few days. When and if I go back, I may bring a smartphone, but leave it turned off unless I really need it.
I remember the first email that I sent out, after having a very hard time on the first day. Rather than go into all the details, I just wrote, "It was hard in every way". Humbling also.
If you have specific questions, ask. I also suggest that you join a Camino email list or forum or Facebook group.