Welcome to EWR
Best places to eat are in Terminal B, in my opinion. However, Terminal C does have a few eateries, but it it mostly in airside.
You can walk up down Terminal C and see a lot of CO
Best viewing may be on the mono-rail (views of runways 4L/R as planes come in / take-off and palnes at gate on all 3 terminals plus remote parking of aircraft).
Car Park P4 (also may be accessed using the monorail) has good views from the roof, particularly runway 29.
If you have time, you can take a cab to Ikea and enjoy their lunch and sit by the restaurant overlooking runway 4. Of course, you can shop as well at Jersey Gardens mall (shuttle bus runs every 30 mins from Parking P4). Outlet mall, so prices are cheaper than regular department stores.
I hope this helps.
Enjoy your stay,
Wasim / Planemannyc