Barcelona to Lourdes

ViaMichelin says it's a 6-1/4 hour drive one way, and that doesn't include any allowance for meal or comfort stops. You'd have to pay for round-trip driving time, and I imagine the driver/guide would insist on the cost of a hotel room somewhere along the way. You might be able to cut the cost (but not the travel time) by taking a train to Toulouse, which is the closest major city to Lourdes, and connecting with a hired driver there.

I'm afraid I don't have any specific suggestions, but I think the best place to look for a qualified guide for Lourdes is in France. Whether a guide is needed or advantageous, I have no idea.

thank you so much. I think time best spent enjoying Barcelona

There is tons to do in Barcelona.

Are you aware that there are quite a few very popular sights in Barcelona for which you'll need to buy tickets somewhat in advance, else they may be totally sold out for the period of your visit? These are the ones I'm aware of: La Sagrada Familia, Parc Guell, Casa Mila/La Pedrera, Casa Batllo, Palau de la Musica Catalana and the Picasso Museum. In addition, there's something soccer-related called the "Camp Nou Experience". I don't know anything about it, but I have the impression that it sells out really early.

Good choice deciding to spend more time in Barcelona. Lourdes is too far for a day trip. If you do eventually get there, a guide isn’t needed since the grotto and church are right together. The rest of the town is little more than a bunch of tourist shops. The countryside near Lourdes is pretty.