A.L.
My church just started setting up play dates for everyone with little ones and I'm also in a MOPS group that has summer play dates. Here are places we go:
Roberts Ridge Park in Newtown
Edgewood Park in Yardley (on Edgewood Road near the Library)
Tyler Park
Core Creek Park
Shady Brook Farms
Tullytown - don't remember the name of this place, but it's behind the fire station and police station in Tullytown. It's entirely shaded.
That's all I can think of right now.