The Newark Reservoir is one of the high points of the city. Quite literally, you can see across the city from the trail that rims the Newark Reservoir. This is a great location to run or walk, it is a little over 2 miles around the trail. It is a little bit of a hike up to get to the top of the reservoir. Luckily the trail is paved the whole way around, as well as the trail that leads to reservoir.
From the trail along the Newark reservoir there is a dirt path. This path is marked and leads to many more trails in the woods. These trails are less populated than the main trail along the reservoir. On these trails you will likely see birds and other critters. I almost always see deer back on these trails, no matter what time of day I use them.
The Newark Reservoir also offers a play ground for the kids. That is clearly well maintained. The parking lot is moderately sized, I have never had an issue parking here.
Also, if you are an avid runner, you might want to join the fusion running club. This run club often meets on Sunday mornings here for a run. Check out the group here.