Big hat, spf 30 fabric shirt and preferably leggings (maybe a wetsuit?), and tons of sunscreen even under the shirt etc. ... it's frustrating, but pale, blond people are more prone to skin cancer from UV exposure than others. A bad burn in childhood sets you up, as you obviously know, Clod, since you're concerned about the sun/water activities.
Living where you do, this is tough. Maybe encourage her to start horseback riding (shameless plug here for the benefits of horse activities for all ages
) - you have to cover up except +/- for arms, and you wear a hat ... it saved my skin back in the day when everyone slathered themselves in oil and lay in the sun.