Rod G......You will have a great time, we have been to Spain now for 3 years since taking early retirement and we love every minute. We don't go until Feb/March though and usually stay till June.
You said you were travelling via Zaragoza and in another thread you have said you are going to La Manga. I have travelled from Bilbao to the Costa Blanca and I would go via A8 then AP68 to Burgos, A1/E15 to Madrid and A31 to Albacete.
There is only one toll road between Bilbao and Burgos and the rest are excellent dual carrigeways. There is also a site very close to the A1/E5 about 20 miles north of Madrid called Pica de la Miel at La Cabrera. (5/6 hours drive from Bilbao)
Also, I use the ACSI website for route planning and finding enroute campsites. If you go to their website and click on Spain, then the region you will find the sites listed. Click on La Manga to bring up the site details. Click on "Itinery" and it takes you to a route plan. Then tap Bilbao into the start point (a drop down box will ask you to specify which Bilbao) select E48000 Bilbao, then your route will be calculated. I find it is an excellent backup to take printed copies just in case the sat nav fails.
Acsi website address is: http://www.eurocampings.co.uk/en/europe/
hope this helps, Mal