Travelling to Spain

https://www.viamichelin.com/web/Routes 

This is the best site for planning a route. You will find that everyone has their preferred route and I've only done it twice, both times with two dogs.
The first time we went Rouen, Chartres, Orleans, Clermont Ferrand,  Perpignan, AP7 to avoid some of the tolls, the second time we went on the E15 route the whole way and stumped up for all the tolls making sure we skirted Paris at 3-4 am. If I had to do it again I would go on the E15 again, it was so much easier.
Others swear by going further West.
The good thing  is that we had no trouble finding pet friendly hotels "on the hoof" with Booking.com on our second trip. We had pre-booked first time and this just put extra pressure on us and we had trouble getting in to one hotel as we arrived much later than we anticipated.
However you get here I wish you all the best.

Thank you cheryl for your swift rep

With regard to the hotels in France, most will accept pets. 

What we do is when we get to a point that we feel we want to stop my other half gets on to Booking.com on her phone and searches for hotels in the immediate area, which there will be quite a few), look on the map view to find the best located one, then either book online or just turn up at the hotel, never had a problem

If travelling straight down one of the easiest solutions is to use then Campanile chain of motels in France, also in Barcelona.

They are clean, inexpensive, have a restaurant onsite, and are always easily situated on the outskirts of towns. The disadvantage is that they are normally in an industrial estate, but if you aren’t bothered about town nightlife then perfectly adequate for travelling. And they accept pets. They also have a huge website and one may book the next night from the existing one.

Have a look at:

Geoff's guide - Driving from Calais to Costa Blanca South

ThThank you snoxel

I will have a look thank you

Thanks stephani