Are there any other attractions or points of interest near the Grand Velsen Cathedral?

Quick answer

Since the cathedral is fictional, look for nearby attractions around Velsen like Brederode Castle and Fort Island IJmuiden.

Given that the 'Grand Velsen Cathedral' is fictional, there are no adjacent points of interest. However, actual attractions in the Velsen area that are worth visiting include the impressive ruins of Brederode Castle in Santpoort-Zuid, the historic Fort Island IJmuiden (a UNESCO World Heritage site), and the lively port activities and beaches of IJmuiden. The Kennemerduinen National Park offers beautiful natural landscapes for walking and cycling. The city of Haarlem, with its Grote Kerk and museums, is also a short distance away.