I live less than 10 minutes from Dollywood, and was there Monday.
You will need 2 days if you want to enjoy all the rides & shows. One of the best perks they offer is if you arrive after 3pm, your next operating day is free. (Through Oct 28). Keep in mind the park is closed Tuesdays now through May 24, and after that, will be open everyday through Aug 15.
The park does offer a lot if you are a non-thrill seeker (it's a lot more than just a "Six Flags" thrown in the mtns). So younger children, elderly guests, etc...can all find things to enjoy.
If you are a thrill seeker like me, you will want to put these on your must-do list:
1. Mystery Mine
2. Thunderhead
3. Barnstormer (< just opened this Spring)
4. Tennessee Tornado
Mountain Ziplines coast extra $$$
If you're a fan of the Disney-style dark ride attraction, you will want to definitely go on Blazing Fury. An indoor ride/coaster that is sorta like putting POTC, Toad, and Big Thunder together in one building. You will see familiar aspects of all three.
Great water rides:
Daredevil Falls: Wet (Splash Mtn)
River Rampage: Wetter (Like Kali @ DAK)
River Battle: SOAKED (Nothing @ Disney/Universal gets you this wet)
Mtn Slidewinder: Just plain awesome. Wetness varies depending on ride. But do NOT skip this!!
While the park does a lot right, one thing they get completely wrong is the motion simulator concept. Maybe I'm just spoiled after riding Soarin', Star Tours, and some of Universal's more high-tech simulator attractions. But Dollywood's simulator ("Wilderness Adventure", though it will have a different theme come Kids Fest this summer), is AWFUL. You just sit in a chair that shakes, while watching a movie screen. Total waste of time & space (imo), and I cannot wait until the park bulldozes that to the ground and puts in something different. That is my one "Must Skip" suggestion. Okay, end rant.
If you want to save on parking $$, go to traffic light # 7 on the parkway in Pigeon Forge. Turn onto Old Mill Ave. Behind The Old Mill on the right, you will see Patriot Park, which is an open field with A LOT of *free* parking. You can park your car there all day, and take the trolley to Dollywood for .50 cents per person. Note, this does take extra time considering you will be waiting on the trolley, which usually picks-up every 15-20 min.
This park pays a lot of attention to detail, so as a fan of Disney/Universal parks, you will certainly enjoy the place.
Hope you enjoy your visit!