Heading to eastern Tennessee next month on vacation. Gonna hit Gatlinburg, Dollywood but whats some stuff ya’ll would recommend? Also going up into Grainger and Hawkins Co as thats where my family kinda came from. Anything to do up there?

Hawkins County I can show you many of the great spots to buy Oxy and meth!
Seriously what are you looking for? I guess you're coming across I-40, are you going into WNC? Are you looking for car stuff or nature? There's plenty of both in the area.

History Stuff, Nature Stuff, anything an 8 year old would like

Floyd Garrets Museum and smokey mountain knife works are cool. Cherokee has lots of cool stuff just across Ten. boarder. If you like fishing lots of fly fishing spots.
Ashville little more distance but lots to do including Biltmore(costly) is cool if never been.

Wheels Through Time

I stayed 10 days in the River Bend Campground in Pigeon Forge last year. That drive over the hills to Cherokee is pretty impressive---saw a herd of Elk on that trip. Plenty to do there. Saw the knife works also. You won't run out of tacky things to see or do.

Floyd Garret's muscle car museum is north of Dollywood and near Smokey mountain Knife Works. The Smokies baseball stadium is right there at exit 407 I-40 also. If you continue on I-40 into NC exit 20 will take you to Maggie Valley where Wheels Through Time Museum is. Right at the TN/NC border there is whitewater rafting. In Maggie there used to be the Soco Zoo.
I don't know how much driving you want to do. You can go from Gatlinburg and drop south on 441 into the Great Smokey Mtns park. From there go further south into Cherokee. You can jump on the Blue Ridge Parkway there and head to Waynesville area. Or you can take the old road 19 and end up in Maggie Valley. In TN off I26 we have a fossil sight museum and they just combined it with the hands on museum which is for kids. Oak Ridge is where they worked on the atomic bomb material and has a great museum of science and energy. Downtown Knoxville at the World's Fair site and you can go up in the Sun sphere. The Museum of art is right there and you can check out the old city and the UT campus. North on I-75 is the museum of Appalachia, and it is great. If you're there for the 4th they will have an anvil shoot, look it up. If you're coming to Grainger county go north on 25e to Cumberland Gap park. great vistor center and go up to the pinnacle. End of July Grainger County has it's Tomato Festival, 4th of July Hawkins County has a festival in Rogersville park.

Hatfield and McCoys, Dixie Stampede, Ober Gatlinburg, theres plenty to do in Gatlinburg/Pigeon Forge, its gonna be hot so make sure you tube down the river!

Bristol Caverns

Tweetsie Railroad! There are steam train rides in Bryson City too. Both in NC mountains.

Cades Cove isn’t that far from Pigeon Forge and Gatlinburg if you wanna see some wildlife and old barns and buildings. With it being summer time, the early mornings and late evenings would probably be the best time to try and see the bears and deer in there. Like already mentioned, there is plenty to do in and around Pigeon Forge and Gatlinburg, especially for an 8 year old

Just a few suggestions, if you're gonna be at Dollywood (Pigeon Forge) and have a few days you may want to take in The Comedy Barn (family entertainment), Tuckaleechee Caverns in Townsend (fantastic), Nascar Speed Park (go carts), Forbidden Caverns in Sevierville, or the total room/cabin water park package at the Wilderness of The Smokies water park resort (great water park resort). Wilderness has a 25% off promo on reservations going on for the next day or so. Check their website for details. There's also Dollywood Splash Country water park. You'll need a vacation to recover from the vacation.

One of the crazier things I have seen is the July 4th parade at midnight thru Gatlinburg. There are dozens of floats decked out with lights, girls, bears, etc. Go to one of the bars and get a seat by a window.