A few thoughts....
You don't say how much time you have, nor give any indication of daily distances. There's no reason to stick to an "official" route, simply wander from place to place with the security of having accommodation at the end of the day.
On road bikes I'd imagine you will miss some of the wonderful remoteness of the meseta.
It is probably the best bike planner out there for those that like quiet roads. It has many features especially useful for multi day tours.
Be careful to select the "paved only" option for your needs.
You will find it especially useful for navigation into and out of urban areas.
There is an iPhone app recently available.
However, no app or router should override common sense.
EV routes are, in reality, a series of interconnected, local routes and as such the quality can vary. Significantly.
Depending on your tolerance for rough stuff they should be approached with caution.
Also, be aware that importing a route created on one planner onto the map of another can lead to problems when the two maps are slightly different. RWGPS will, for example, show alternate routes for the same start and end points if a different map option is displayed.
I understand the need to "have" a route but the reality is that Spain is close to a paradise for bike travel. It is very, very easy to get around and if anything, a rigid route does a disservice if while going from A to B you miss C. My suggestion would be to find out where you want to go then plot a route to go there as opposed to following a route someone else created.
If you're not used to using a phone to navigate bear in mind that power usage can be high (pack a power bank), the screen can be hard to see in bright sunshine (or in rain!), the phone can be prone to overheating and is vulnerable in the event of a fall or crash.
Also, turn by turn notifications are not what they seem
Buen Camino