Rule of thumb typically closer to Pigeon Forge more trout less smallies. Apple Barn by you is a good starting point and about the end of trout beginning of smallie water.
Smallies:
Park in shopping center then cross road go either upstream or down
https://www.google.com/maps/dir/Pin+...d35.822561!1m0
Park at Walgreens cross road and go either upstream or down
https://www.google.com/maps/dir/Pin+...d35.822561!1m0
Directions to the East Prong at Red Bank area. This is about the middle point upstream towards mountains is trout more so and down towards Sevierville is smallie/rock bass more so. There are pull off scattered since the road follows the river for quite a ways.
https://www.google.com/maps/dir/Pin+...d35.822561!1m0
A lot of locals fish the Park in Sevierville while I haven't it does have good fishing.
https://www.google.com/maps/dir/Pin+...d35.822561!1m0
These are just a few but also keep an eye out heading between the last red light in Pigeon Forge going to Gatlinburg for the various pull offs. You can fish those as well for trout. Once in the city of Gatlinburg you can't fish on Thursdays and you have to have a city permit. It's an extra step to get to fish by buying the permit buy really fun while your wife shops all day in town you can fish the stream easily walking it. The hop out grab lunch and a brew then repeat or sight see.
Hope this helps.
Also I didn't mention always ask locals where ever you go. Find a shop (Orvis would be convenient to you) for the up to date info and places that may be hot. Wal-Mart up there is fully stocked with everything you will need and if not Orvis might but Bass Pro back by I-40 definitely should.