Off-season use of a car on Zion Scenic Drive
 

I'm a little confused as to what the car-vs-shuttle rules are for Zion NP in the off-season. My interpretation is:

1) If the shuttle IS running, then you may NOT drive your car on the scenic drive.
2) If the shuttle is NOT running, then you MAY drive your car on the scenic drive.
3) If condition 1 applies, you may still use your car ONLY to go between the outside world and the Zion Park Lodge, and only if you have a pass.

I'm looking at going to Zion the first half of the week of Thanksgiving, when the shuttle is not running. Am I correct in that I will be able to drive the whole length of the scenic drive, subject to a capacity control imposed by the National Park Service based on the total number of parking spaces?

I believe that if the shuttle is not running, you can drive all the way in. There isn't much parking and most of that will be taken by people who are staying in the lodge.

Confirmed lodge residents can always drive there year around.

Now for the rest of your question:
This is Zion's shuttle guide.
https://www.nps.gov/zion/learn/news/...ALL2016Web.pdf

Many word, scarce information of when you can drive to Sinawava (scenic route). It has to be inferred.

Government publication

Vaga

Confirmed lodge residents can always drive there year around.

Now for the rest of your question:
This is Zion's shuttle guide.
https://www.nps.gov/zion/learn/news/...ALL2016Web.pdf

Many word, scarce information of when you can drive to Sinawava (scenic route). It has to be inferred.

Government publication

Vaga

#1- true. You may not drive the scenic drive if the shuttle is running
#2 True. If the shuttle is not running for the day/season private cars are allowed on the scenic canyon drive all the way to the end. Parking lots are small and parking will be limited. In the past cars (despite "no parking" signs) were parked on the roadside. I've heard they may be cracking down on that as it does present a hazardous situation.
#3- True. Reservations at the lodge allow you to drive to the lodge- no stopping along the way.