If you are going to be there two days or more, buy a season pass. It's cheaper than 2 days worth of tickets. You can save on parking by turning down Teaster Ln and parking at Patriot Park for free, then riding one of the Pigeon Forge trolleys in. It costs 50 cents per person each way, so if it's a really big group of you it won't be worth it, but 4 people or less would be cheaper.
DO NOT miss a ride on the train. It's one of few remaining coal-fired steam engines in operation at an amusement park. It will take you on a 5-mile round trip up into the mountains and back, where you also get some nice views of the coasters. Dollywood is very proud of their train engine Cinderella (and their second engine Klondike Katie) and love to show her off. You can hear her steam whistle echo throughout downtown Pigeon Forge.
The food is amazing. There is no bad, or even mediocre place to eat. However there are some shining stars. Ms. Lillian's Chicken House is an all-you-can-eat buffet with fried chicken as the centerpiece, but plenty of other great home-cooked options. You also get to experience the entertainment that is Ms. Lillian, the chicken lady, a fantastic character that roams the dining room singing songs and generally finding every way she can to torture unsuspecting victims in the funniest way possible. I've seen her dress DaveStroem up as a chicken to dance with her, ask to borrow someone's cell phone mid-conversation and then sing a chicken song to the person on the other end, stalk people to the fountain drink machine, and everyone's favorite, provide chicken blessings to those in need! If you like to have a good laugh, this is not something you want to miss.
Another good place is Aunt Granny's, a full-service buffet full of home-cooked favorites such as turkey, fried chicken, pulled ham, stuffing, mashed potatoes, etc. Hickory House is a "quick service" establishment that serves BBQ pulled pork sandwiches and turkey legs. Lumber Jack's Pizza is the home of the 12-lb pizza, which they serve in 1-lb slices. They are also the home of the best chicken tenders in the park. Other great places include Backstage Restaurant, Market Square, Red's Diner, Dogs n Taters, Victoria's Pizza ... the list just goes on! Definitely plan to eat in the park. It's not as expensive as KI, but is a bit higher than you'd find in the 'outside world.'
If you enjoy shows, Dollywood produces some amazing ones. These aren't the type of shows you will see in a chain park. They won the "best shows" Golden Ticket for a reason - beating out even Disney for the honor. I recommend Dreamland Drive-In and Wings of America. The Christmas shows I think are phenomenal, so if you get a chance to go back during Christmas you could spend an entire day just watching shows.
Oh, and of course, I recommend riding every coaster. Don't skip over Blazing Fury - just remember to appreciate it for it's 1970's cheesiness. And come say hi to me at Wild Eagle!