I want to focus this review on the National Park itself. It is the only National Park in the United States that doesn't have an enterance fee. There is an information building at the base of the mountains in Gatlinburg. You can get maps and information from park rangers there.
You can drive to the top of the mountains. Along the way there are many pull outs you can park and take pictures. There are also trails you can hike. It is posted how long the trails are and if there are things of interest on them such as a waterfall. Remember about the altitude difference. We have a found it's about 20 degrees cooler at the top of the mountain than it is in Gatlinburg.
While in the mountains you will see a lot wildlife. Your standard birds, bugs, deer and if you are lucky, a black bear. We have been on several trips here and have only seen a bear once.
One fun thing to do is drive the Cade's Cove loop. It starts in the valley of the mountain and winds around. You'll see wild horses on this route. There are many historic homes and churches you can get out and look at. It does take about 2 hours to drive the loop so be prepared with snacks for little ones. There is a place for a bathroom break a little over half way through.
The really great thing about the Smoky Mountains is they are beautiful no matter what season you come. Spring has the new vegitation starting. In summer everything is green and the trees are a sea of leaves. Winter leads to beautiful ice that looks like it is melting down the mountainside. Fall of course has the vibrant autum colors on the trees.
All of this is done without paying a penny. Just the cost of gas in your car. This is truly one of the most beautiful places to be at one with nature.