I live 45 minutes from Gatlinburg. You'll be amazed at how Pigeon Forge and Sevierville have grown. The stretch of 66 from the 407 exit to the light at Chapman Hwy. is heavily developed now, and the 407 itself is growing tremendously. They just opened a huge Bass Pro Shops at the exit, and the baseball stadium overlooks the interstate there as well. From Sevierville to Pigeon Forge there is little to no empty space left. Traffic is horrendous every day, especially through the park as you head toward Gatlinburg. If you can, take the bypass around Gatlinburg and come in from the other side. It will save you a lot of time and frustration.
The Apple Tree Inn is very popular, but there are many others. I'd prefer to head into Gatlinburg instead of the Forge for food. There is a more eclectic selection. Burning Bush is gone, but there is Greenbrier, Hofbrauhaus, the Pancake Pantry, Applewood (in the old Burning Bush) and so many others.
You should be able to get over the mountain to Maggie Valley in May, but if there is a late snow the highway through the park to Cherokee *will* be closed. If school is out, or it's close to Memorial Day I wouldn't even consider going that direction, as traffic around the casino can be nuts. The drive itself is beautiful, though.