my favorite creek walk is shining rock wilderness (along the bottom there, to the waterfalls) ... but that would take a bit to get there and a good hike down.
another good place that’s easy access is the laurel river in madison county. come up I-26 to weaverville, take the marshall exit and head past marshall toward hot springs. just at the left turn toward hot springs on 25, there is a parking lot on the left with a trail that leads down to the laurel river (easy 5 minute walk) ... lots of places there to wade, swim, rock hop, laze about, hike, etc. very nice for kids ... you can venture out as far or as near as you wish from the car and there’s a nice canopy of trees to cool you off ... occasionally, you even see folks floating by!
if you really want to thrill him, there’s a garnet mine with a creek where you can find whole garnet crystals! (i have found hundreds, with the largest so far about the size of a plum, with perfect 12-sided facets!) treasure hunting is fun for all ages ... and this is the real thing, not the roadside buckets. there’s also a cave (less safe for kids, but still okay if they’re supervised) but i stick to the creek and have spent entire days sifting through the mud and chillin’ my feet. post here or email me if you want more info and directions ... (there’s a great local rockhound group that makes field trips on weekends and welcomes kids ... check out wncrocks.com and click into the MAGMA club links ... these guys are the best!)
have fun!