We are taking a family vacation to TN,mainly the gatlinburg/ pigeon forge area any suggestions?

I have 3 children 11,6 and 4 I want this to be a great experience for them and a start of a summer tradition.But I need some ideas on things to do there I have only been once in the winter.I would love to take a short hike to see a waterfall and maybe have a picnic there but I want to make sure it is safe for the kids.I have been looking at one called Grotto Falls in the smokey mountains but I haven't made up my mind.Any suggestions would be helpful.Resturants,attractions,outdoor stuff we want to do it all!!!! we are already going to dolly wood and ripleys:)