Usually if you have a Correos mailbox, you will find a slip in the box to tell you that you have a parcel. so you just ask for it. Similarly if you have a buzón at your door (and you are out) or at the top of the road, you get an advice slip.I have had the same idea, although not in the same area and not a very remote one.
If you get a PO box will they accept parcel or is there another service altogether?
Maybe if you know the courier companies you can organise in advance to be notified when you have a parcel and just go to the depot to pick it up.
In my experience, yes, they will.That is something you will have to take up with your local Correos office.