Spanish sites in April/May

Annie33

I've been reading discussions about how busy Spanish sites can be in winter. We are planning our first trip to Spain from the middle of April until the end of May, starting in the Costa Blanca and then the Costa Brava. Does anyone know how busy the sites
are likely to be by then and would we need to book in advance? We have a large twin axle caravan and know from towing in France that not all sites have big enough pitches. Are we going to find the same problem in Spain? Many thanks if you can give me some
advice.