You'd be a fool if you don't take the opportunity to visit.
Important things i can think of for now:
Watch as many videos as possible. Try to learn the track on Gran Turismo or Assetto Corsa(great one). And no matter what, remember that on your first lap everything you've learn will be pretty much useless. Learning the track on videos or simulators will help knowing where the corners are headed but NOTHING will prepare you for all the elevation changes and blind corners. And there are lots and lots of elevation changes. It's a freaking roller coaster. Seriously.
Take it easy, watch your mirrors and you'll be fine. Just enjoy the drive while you're at the best track on the world, period.
Weekends are just for show. Forget about lapping on a Sunday, too much traffic, too much "heroes" trying to impress the big crowd(just go and watch any Brunchen videos on a Sunday, it's ridiculous). This also means the track will be closed most of the day.
To give you an idea, here's what a typical Sunday is: from 8:00AM to 10:00(approx) there is not much traffic, people still getting there. If you get up early in the morning you can get some decent laps if you are lucky. From 10am, it's just caos. Long queues to enter. Long queues to exit. Crash/incident >>> the track is closed. Everyone takes that time to see the cars on the parking lots. When the track opens again, you will see a lot of people RUNNING to get to their cars and try to be the first on the line. As you can imagine, this means the queue to enter will take you longer than completing a lap. And considering how "eager" some drivers are on that "the track is open again let's go as fast as possible now" lap, sometimes you don't even get to enter because some idiot crashed AGAIN before you even got to the track entrance.
Weekdays are ideal to do as many laps as possible, little traffic, no drama. And this year laps will be cheaper as well.
Regarding rentals, i'd go with
http://rsrnurburg.com great people working there, and plenty of cars to chose. BTW they have a lot of youtube videos showing the track for beginners. Must watch!
Rent4ring has a big offer too and is well known.
Apex Nürburg is a "new" business and has a MY17 fully loaded(JRZ suspension, full HKS exhaust+ecutek for now, rollcage, bucket seats, semislicks, etc coming in the next few weeks). I'd put my money on that one if an 86 is what you want.
They will offer acomodation as well once their new hotel/building is finished.
Places to sleep there's plenty to choose, i can recommend Hotel Am Tiergarten and guesthouse Haus Ringblick, not the cheapest but they are as close to the track entrance as you can be. Adenau is a great place to be as well.
Food is great, specially italian. You won't go wrong with these restaurants: Pistenklause, Pinocchio(amazing pizzas) or the Ventisette.
Hope it helps, feel free to ask!