Beamish
We went on Saturday and it is a fantastic day out. Well worth the journey and the cost.
3yo DD loved the whole thing - ride on the tram, going in the drift mine, singing in the church, baking in the cottages, going to school(!), the sweet shop, the fairground, ...everything really. LOL!
We took a picnic as the weather was fine and there were loads of places to sit and eat. And you can go back and forth to the car so no carrying heavy backs.
And it is really a full day out. We gott there for 10am and didn't leave until 5pm, when it closed and we could have spent longer there easily.
If you're in the area, consider this!