It's about 400km or so from Calais, all along the E40 for a good while, if I remember correctly. Motorway for 90% except for when you hit the local B roads. To roads most if not all the way are like silk to drive on.
Mid-week is far better than weekends, but many weekdays are booked by companies for testing. It is much more quiet on a monday and especially tuesday. Unfortunately, the Ring taxi may not be on mid-week. Check the offical site for what events are on, although at this time of year everything is finished I think, and ADAC don't have any events but I may be mistaken.
Price was €16 a lap last month (start of October), €56 for 4, and again a little discount for 8. Then it's around €350 or so for a half year pass or €780 (can't remember the exact figure - I am no Ring meister!) for a year.
For the hotel, The Dorint Novotel am Ring is excellent, and very thematic. It's also right next to the ring museum. The weekends can be expensive - Fri Sat Sun can run a few hundred per night, but on the Monday our rate was €128 for two (depends on whether you want to face the Nurburgring starting grid or not). It is around 2-3km from the Nordschleife entrance.
before you go near the Nordschleife, make sure you have checked all essentials (tyres, brakes, etc., ). You are totally responsible for your car - there are no guides, no introductions, no requirements other then roadworthy car and legal license, etc., . It is a public road.
If you go on a weekend, be prepared for lots of closures - if there are bad accidents, they will stop letting people through the tolls until it's clear, might be twenty minutes, might be shut for the day (happened last month when I was there - on the Monday, they shut it at around 1630 - they were peeling bikers from M5s, very scary **** indeed). The weekend was much much busier, as ADAC had some endurance race on, so it was like a car park for the tiny roads around it, parking on local field, etc., .
There is no petrol station there, but there are two nearby - one which is closest does not sell high octane petrol (100 octane, like you get in the other Aral stations).
It is not expensive at all and is a great experience, but can be terrifying if you spin off the track, cross back over it perpendicularly and then 5 seconds later a torrent of bikes and cars misses you by a foot! **** can wrong really really really quickly. Bikers are nuts. Overtaking tour buses is harder then it looks!
I would recommend splashing out on the Ring Taxi (€170 - probably fully booked for months on the weekend, but managed to scab a few seats on a weekeday is easy enough IF the taxi is going on a weekday).
Make sure your car is in top notch condition. Brakes especially and tyres. A few mates didn't get tyres sorted beforehand and had a nasty impromptu meeting with a wall.
Like was said above: it is risky, BUT, you don't have to push it, although it is tempting to.
Oh and cameras are banned in the cars, although they are allowed at the "toll side" entrance.
Where abouts are you based tho as this might just affect how long it takes to get there 
