We went to one holiday in Tenerife, making well sure we went mid September a long way from the end of school holidays. We had just looked after grand-children for 1 week, which we loved- but needed a good rest. We had kid's club doing the lambada and kareoke all day long next to and around the pool.
NO! We asked to be moved to another Hôtel - peace and quiet- bliss.
Our idea of a holiday with grandkids is to be in the woods, or by the sea- away from it all- exploring nature, looking at beach pools, doing sport and fun activities and games. Each to their own of course. If I ever di go on a cruise, it would be for a total cabbage holiday. For me, personally, a cruise with kids just does not compute.