As others have suggested, I would recommend John Brierley's 'A pilgrim's guide to the Camino Ingles'. It often provided useful detours when road walking was likely to be aversive and was thorougly inspirational to boot! A wonderful guide.
For Paradores - You will find that you can join as an Amigo on the official website (no cost involved). It gives you access to special offers and also you are usually offered a welcoming drink of wine or beer.
A really good website for many long distance options in Scotland is https://www.walkhighlands.co.uk/long-distance-routes.shtml. It has some details of accommodation as well as the routes. May is often the best month with not so much rain but...
I don't know your home country but you can get a credencial before you go. In the UK contact the Confraternity of St James or in the US from American Pilgrims on the Camino. That way you arrive with your credential and can leave as early as you...
I walked the Camino Ingles as my first camino last year and wondered where to get stamps initially. Getting into the habit of asking anywhere you stop helps a lot. Looking back at my credential stamps came from tourist offices, council offices...
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