Some of my favorite shoes to wear in the parks are Eliza B's. They're super comfy and not like a normal flip flop, they actually stay on and support your footbed. And they're not that spongy material, they're a little harder and stand up to alot of wear. My favorite pair is the madras, they're so soft, you just want to be careful with some of the ribbon ones, the edge can be a bit rough before they get broken in.
They even come in kid's sizes!
http://www.elizab.com/
Sandals
http://elizab.com/Merchant2/merchant.mv?Screen=CTGY&Store_Code=EB&Category_Code=SAN
They even come in kid's sizes!
http://www.elizab.com/
Sandals
http://elizab.com/Merchant2/merchant.mv?Screen=CTGY&Store_Code=EB&Category_Code=SAN