How wonderful to be carrying the spirit of your father along The Way with you. We walked our Camino Portuguese this past spring in honor of my wife’s father who also passed away in 2020. We added his name to our Compostelos “vicarie pro.”
You are correct tha the municipal and donativos are less expensive and it’s on a first come, first served basis. No reservations taken! Due to being less expensive, most are first choices by many. Getting there early is a must, but that still doesn’t guarantee a bed. I do think you want to reserve a bed in an albergue in SJPP, Roncesvalles, and Larazoaña/Zuberi. By the time you reach Pamplona, you’ll be a veteran and have a good idea of what’s in front of you regarding crowds and albergue beds.
If you’re not familiar with it check out Gronze.com for places to stay along the CF. Some reservations can be made via Booking.com. For others, you’ll probably need to contact them directly by email as is the case for the Monestario in Roncesvalles. Now, is not too early to start making reservations for the first few days. Good luck.