Hiking with kids can make you want to run and hide in the other direction, especially when you are taking nieces, nephews, and cousins aka children you can not ground for poor behavior and aren't accustomed to hiking safely.
However in Fresno there are great ways to get our hike on with kids and still save your sanity. The first is to go to Woodward Park. The main section of the park is enclosed with gates and charge a fee to get into the park. However if you continue to the Audubon intersection where there are residential houses north of the main entrance you can park in the residential area for free. The great thing is that there is no limitation on time. You could be there all day. As a courtesy to the residents, and to help ensure there are not complaints, you may choose to park on the side of houses instead in front to save the prime spaces for residents.
Then you just grab hands and form a chain and walk along the sidewalk on Audubon and cross over to Woodward Park. There is a gate to walk in. The great thing about entering here is that you are well past playgrounds and grassy areas where kids can scatter and get lost. Instead you are on a relatively straight paved trail with brush on both side for the majority of the trail. This minimizes the chance of kids going off trail. Additionally it is less populated here so you can start sing-along and word games as you hike without fear of irritating neighbors. As an added benefit there are plenty of birds and squirrels on route in addition to flowers and plants to keep the children's minds active. About 2 miles into the trail there is also an area with a clearing that you can stand in and see a quarry. This gives a great chance for you to educate the children about mining. If all this wasn't tempting enough there are periodically drinking fountains and rest rooms along to way for stops and nearby benches to sit on while you wait for the children to get drinks. All in all it is a great way to keep control with a large group of children and still show them the beauty of nature.