While our GD (now much older than 5) loves rollercoaster type things, we don't. Nothing sounds worse to me than spending several days at a theme park (one day, maybe!).
She lives a distance away so staying with us is a holiday in itself. We go out for days - castles, beaches, caves, lead mines. Always a mixture of things to broaden her experience and so that at least one will be really interesting for her. One time she went to a craft workshop at the Glass Centre. We took her to Edinbugh for a couple of days - Mary King's Close, the castle, the zoo...
So I'd suggest going somewhere where there's a variety of different attractions within a short distance.