There are different travel possibilities to Spain.
If you go by car, then you will have a journey of 1400 kilometers on your bumper (coming from The Netherlands), especially if you choose the toll roads, the most expensive option. This is only feasible if you travel with more than two people and can change drivers. Otherwise a night on the road is recommended. But perhaps you will want to have a car at hand while you are in Villamayor or Viana.
There are train connections with Pamplona and Logroño, but then you will need to make frequent transfers also travel part of the way by bus. This is only reasonably inexpensive if you book early or can take advantage of a special offer.
The Euroliner bus is reasonable out of season and stops in Pamplona and Logroño. But this is a very long sit.
by plane in combination with bus or train
If you travel alone or with someone then this is the quickest option, the cheapest and the most comfortable.
We cannot give advice about the best flights because offers continually change. It is a matter of finding the most favorable flights which land as close as possible to your final destination. Search, for example, at www.tickets.nl of www.wtc.nl.
Flight prices can vary enormously per day.