Best route to Costa Dorada, North East Spain

The Cardens

We are hoping to travel to Spain, staying at the Playa Bara, Tarragona, Costa Dorada at the end of July 2014. We have read many posts and looked at various websites for the best routes but feel overwhelmed as there seems to be so much conflicting advice. 

We would be grateful if anyone could please advise us as to the best route through France from the Channel Tunnel at Calais avoiding Paris and using a mixture of tolls and toll free roads.

Thanks