Hi Twinkletoes
We too love camping! Have been to Sanguli in Salou, Park Playa Bara in Tarragona and this May / June to La Siesta.
Usually we book accommodation with the campsite direct. At La Siesta we went with Keycamp, who were great, and the mobile homes new and well equipped and very comfortable. My eldest met some friends who were with Camping Life and he thought their mobiles were better (prob because they had Sat TV!).
We drove to Marineland (water / dolphin park) during our stay (about hour and a half drive), which was good (but not a patch on Portaventura). I would not have attempted to drive to Portaventura, as I felt it was too far. They did do coach trips from La Siesta, but they hadn't started yet. (I think it would have taken about 2.5 hours to drive there).
There were two other water parcs in the area, which weren't yet open (opened at beginning of june) - Aquabrava (closest to La Siesta) and another one in Roses (name escapes me!).
I found the beaches around the campsite unsuitable for my six year old to go in water alone. Shingle which was hard on feet and a strong undertoe and water which went deep very suddenly. Had to keep hold of him at all times! But it was fairly windy.
We went to a couple of local markets in surrounding towns and go-carting.
We had a good holiday, the kids loved the campsite as they made friends with other kids - there were a lot of English kids as it was half-term, but I think my favourite so far was Sanguli (between Salou and Cambrils). I don't think you can beat Portaventura for entertainment for all the family.
The scenery and towns are very picturesque (more so than Costa Dorada)in the Costa Brava, which we liked, plus it felt very safe.
Hope this helps.....feel free to ask any questions.