Suggestion 1: Get a copy of the book and read it. These, and lots of other questions you'll probably have are answered in there.

To your questions - Dr. Atkins states that exercise is an important part of any healthy lifestyle. If you can incorporate it, there's really no reason not to do at least something on a regular basis.

On the dressing - almost anything is low carb. If you aren't making your own, just check the bottle. Italian, ranch, bleu cheese, caesar...all LC.