This time of year crowds can be hit or miss. It's basically based on weather, a beautiful Spring afternoon will be packed on the weekend.. If it's packed, you might need a day and a half. If not, one day is plenty. My suggestion is one day with timesaver (if busy) or 2 or 3 day pass and spread out the visit. Especially this time of year when the mornings can be cold, I'd visit afternoons. Personally, if I wasn't local I would do the three day pass, only $10 more than the two
I'd also suggest a weekday visit, if it's warm and pretty, locals flood on weekends making it extra packed
A few years ago I would have told you to come in after 3:00 so the next day is free but they ended that and I don't imagine it will ever come back. It was a nice perk for folks in your situation
For other activities
1.) Hit the mountains! Do a short hike or nature trail
2.) I love the aquarium, yes it's a corporate Ripley's but still a great aquarium
3.) Walk around the island
4.) Visit my wife who manages one of the outlets in Tanger! Who doesn't love outlet shopping (yes I know, most isn't the same quality as the "real" stores).
I spend money and shop when on vacation, some like this some don't
5.) Pick a mountain coaster or two
Dollywood Tips
1.) Water is free, just ask. Don't waste money on bottle water unless you are the type who won't drink the water from a soda machine
2.) If you have ever been to Disney, Universal, or six flags and have a Fuelrod swappable battery bring it! Dollywood has the swap machines. The one in the emporium is down right now but the other three work. I know these things can be expensive BUT they have saved me thousands of times at Disney, and much easier than carrying a power bank (hint you can buy them on Amazon and trade at Dollywood or Disney. Just search fuelrod. On Amazon two are the price of one at Disney or Dollywood) (Setup the app so you have free swap credits! Dollywood has a small swap fee if you need a fresh one. Under $3)
3.) Sunscreen! Bring it!
4.) It can be a hike back out to your car so bring a backpack for important stuff if needed BUT they don't allow food or drink in the park. You can probably get by with a pack of crackers or energy bar, I have. Personally I hate backpacks in parks but that's just me
4.) Hit LR first, it was down the one visit I have been this year. Not sure if it has been up at all to be honest.