It was a good event and we'll certainly go back.
The signs for the entrance take you around to the back of the track. There you drive through one of the tunnels under the track to the infield. They have the tunnel lit up with Christmas lights and it looks pretty cool. From there you drive through one end of the infield (turns 3 and 4 and 4). We all enjoyed the light displays.
They also tell you to turn your radio station to 91.1. They are broadcasting Christmas music for you to listen to. Once you drive around the displays, you head out to the track. Unfortunately they have the track itself closed so you don't get to drive up on it.

You do get to drive around the bottom of the track, though, between the track and the inside wall. They then have you drive down pit road. You can also see a bunch of lights setup in the front stretch grand stands which are choreographed to the music.
Near the end of pit road, you are directed back into the infield where there is a parking area. You can get out and go to the 'garage area.' One set of garages has some vendors setup there selling various things. They also have an indoor ice skating rink that you can do for $6 + $2 for skates if you need. The other garage area has Santa, Santa's workshop, and a bunch of trees decorated by local businesses that you can walk through and enjoy. There are also a few vendors in this area too.
Between the two garages there is a stage (that wasn't being used when we were there - possibly because it had rained recently and it was a Tuesday night). There was also an area with campfires setup where you could roast marshmallows. I didn't look into that much, but it looked like you needed to provide your own marshmallows. There were also some Nascar souvenir trailers with discounted merchandise and some other food vendors. I must say the funnel cake was awesome. It was only $5 for any/all toppings that you wanted.
At the other end of the area between the garages was a live nativity and streets of Bethlehem. That is always cool to see. Behind that were some bleachers setup so you could sit and enjoy the 25 minute light show on the front stretch. When you left, you went through the Lowe's patriotic display, then around turns 1 and 2, then exited through the back stretch of the track.
Beyond the last set of garages was a petting zoo and some flat rides for the kids.
So while $20 per car (up to 8 people) seems like a lot initially, they really crammed a lot into it and we felt like we got our money's worth. We spent over 2 hours there and about $30 total. Everybody had a great time.