It doesn't make you a monstrosity
Ah, it's the very act of travelling by bike that makes me a monstrosity for some on here.
At the risk of excommunication from the forum, aside from the Camino routes there are many long distance hiking routes in and around Spain. They are normally labelled as GR with a number after GR. Some Camino routes use part(s) of these.
There are also Via Verdes, usually old railway lines of varying distances between towns. With discretion, many of these provide an opportunity for some stealth camping.
It would be entirely possible to create the perfect (for you) hiking trip by hiking in different parts of the country for days at a time, linked together by bus or train. A few days along the coast, a few more in the "Spanish Lapland", some days in the mountains in Catalonia.......
This would be very different to travelling a traditional Camino route in the sense that infrastructure could well be significantly less and information may be harder to come across in advance. And of course, Santiago is not a destination (although, I suppose, it could be).
It would, I think, give a different perspective of Spain, too, away from the "Pilgrim experience".
Mountains, sea, seclusion, all could be found with a bit of research. Language would become more important. Self sufficiency, an essential.
It's interesting to note the hint of electricity in the air on this thread stemming from the idea of "real" or "true" pilgrims and pilgrimages. Nothing terribly explicit, but it's there.
Magical things can
happen on the Camino. But in my experience it's the mindset that the Camino supports that creates the magic. It is always within us, we just needed to find a way to tap into it.
More heresy, but it is possible to develop that mindset away from the Camino. It's just more difficult.
That said, there is a lot to be said for travelling a well worn route that people have travelled for centuries and are travelling in common with us in the here and now.
And a lot to be said for day after day travelling by the same method and at the same pace. Psychologists can offer insight into how long we have to do something before it is a habit. The simple priorities of "Camino life" - find food, water and a safe place to sleep - can become ingrained and help us to be grateful for the simplest of things. A new habit.
We don't know how your patient described their Camino experience to you. Was it full of sights and beautiful, old towns perched on hilltops that draw us along and up through fields full of life? Were they tales of pushing ourselves to our limits in scorching sun or pouring rain and prevailing? Were stories told of evenings spent over a vino tinto with strangers and the freedom that comes from speaking openly and learning about people from far, far away? Was there mention of the great bond that can grow between people as they travel in the one direction over a long time? They hardly spoke of all the snorers or the very early, plastic-rustling risers, or the blisters did they?
Whatever it is, the Camino is not just another hike. It has levels.
I understand fully the desire to be alone and away from the madding (or maddening) crowd, but to actively avoid the other participants, especially as a first timer, is, I think, to lose one of the "levels" and one of the supports of the Camino experience.
Those other participants are not always pleasant or enjoyable company but we can learn a lot from them. And about ourselves.
(Some of them, of course, are great!)
If, and only if, trying to uncover all the levels of the Camino is one of your objectives I'd encourage you to keep that in mind in terms of your decision making. The quieter Camino routes will have advantages and disadvantages for that goal. Aware of the disadvantages we can work to negate them and take full value of the advantages.
I don't know if it's possible at this stage but I think that having done a bit of research talking again to your patient who has inspired you might be a good exercise. Perhaps patient confidentiality is an issue but many Pilgrims past, present and future are members of Camino organisations in their local areas. I don't know of anyone who has travelled who doesn't want to talk about it!