Green Timbers Park Information link listed above--easy for strollers and kids to walk around. There's a lake and picnic benches to have lunch. There is great information for kids about nature and the many different type of trees that grow in this park at the Surrey Nature Centre and some interactive activities to do too.
Can meet up at the Surrey Nature Centre as there is a nice parking lot there.
Here's a link about this information. http://www.surrey.ca/culture-recreation/2311.aspx