Hi panmanlives,
That sounds like a great itinerary for your family and I wouldn’t be dissuaded from visiting Puerto Viejo. We spent a month there last year and like you said, it is a gorgeous area with a lot of natural beauty and culture. It does have more crime than other areas of Costa Rica, but the stuff you hear about usually happens late at night in bars, clubs, etc. Just going out and doing normal activities with your family, you shouldn’t have any problems. The biggest thing to watch out for will be petty theft. If your vacation rental has a safe, lock up valuables in it when you leave and don’t bring anything valuable to the beach. The area near Banana Azul is really nice and quiet since it’s a little outside of town, but also close enough to other things so that you don’t feel too secluded. We think you’ll really enjoy it. Have a great trip!