In 1906, the Watsontown Memorial park was created as a "pleasant place for strolls and baseball." To this day, 110 years later, this is a popular park, with a great little mini fitness area, some basketball courts, and great views of the river. The baseball fields are still here, and still used. There are benches and swings near the river, and pavillions for picnics. More of the parks history can be found here - http://www.mywatsontown.com/?page_id=42
There's a large festival and car show held here after the 4th of July parade, and the fireman hold a carnival here the second week in June each year. The cache will be very difficult, although not impossible, to get to those two weeks.
All summer long a local church provides FREE lunches for kids every weekday, and often they have activities for the kids as well. Some stealth may be required, depending on the day and time.
"Founded in 2013, volunteers from the church provide FREE cooked lunches every weekday of the summer (except July 4th) at the Watsontown Memorial Park. This lunch program is open to any/all school-age children, regardless of school district or family background. This ministry’s conviction is that none of our communities’ children should go without a nutritious meal or some heart-pumping fun at the park. Kids’ Cafe: Watsontown is staffed by volunteers from Watsontown UMC and other individuals from the community who care and wish to invest in the lives of children." http://watsontownumc.org/ministries/kids-cafe/