So, my parents left the country, and left their 1996 XJ12 for me to hold for them, for when they come back to California for visits.

My brothers had recently used this before my parents dropped it off at my place, and the condition is poor; they really didn't take care of it, or were just really careless and abused it. I.E. cigarette smoke scent, headliner low, mirror switch broken, windshield cracked, antenna broken, dents, scratches, leather worn, etc...

It drives, but the plenty cosmetic problems are just very sad.

My questions are:
What is the difference between the S and the N next to the Drive switch? And which saves gas more, because of course Premium gas is not cheap.

Also, being that its in the N mode right now, is it normal for me to really push down hard on the Gas pedal to get the car to move?

There's a light on next to the Coolant level gauge, is this normal?

Anyways let me know.

Thanks in advance for your responses.