Portugal Family trip?

My husband and I are planning a trip with our 3 children 14,9,4 to Portugal. We want to stay for at least 2 weeks. We want to go next Oct or Nov. They all surf to so that would be another thing close to good surfing beache's. We have been a few times buy ourselves and love it. What are the best towns that are very family friendly. We have only traveled north of Lisbon and the furthest was Porto. Or if any other countries that are not extremely expensive we do have a budget.