Knoxville and snow-
You're the guy trying to find a nice four season balance right?
Knoxville is a somewhat milder four season area.
You will get some snow, but it won't won't be consistent and most of the time it won't be much.
//www.city-data.com "Knoxville Big Snow"
You would maybe keep an ice scraper with snowbrush in your car, and maybe a snow shovel if you are too impatient to wait for the sun to melt the snow off your walkways.
It is one of those areas that tends to shut down if there is more than 5 or 6 inches of snow (rarely happens) and people run out to stock up on toilet paper and milk the night before.
If you like typical winter sports like skiing you'll need to drive up into the mountains, Gatlinburg or some of the places across the border in NC.
But it is a lovely area and if you enjoy outdoor activities it's a great location. Close to the mountains,lots of nearby parks, waterfalls, rivers, lakes, caves, all kinds of fun things.
Tennessee Landforms maps
Fall is gorgeous in this area and there are some spectacular drives to be had through the mountains. These are some great pics from one of our forum members.
//www.city-data.com Kamoshikas pictures This is NOT Knoxville, it is about an hour east of there, but it gives you an idea of the scenery to be had nearby.
I'll leave the discussion about what there is to do for young people up to others. My kid is in his last year as an undergrad there and he enjoys what there is to do, but I imagine it might be a little different from what a young couple would be looking for.