I've a Nikon D5100. How do the following in-cameara settings affect the RAW images produced by the camera?
- Auto distortion control
- Long exposure NR
- High ISO NR
Or is it better to go with Adobe Camera RAW?
None of those settings affect RAW images.
They do affect JPEG images by reducing noise and details simultaneously. They do not give you the ability to print larger and which level you prefer is a matter of personal taste. At very high ISO, images look soft or noisy and eventually both.