We went to the beach yesterday that the mother says they swam at often. It's nice, for Iowa. I fear you may be correct. I saw a vehicle cruise slowly through the parking lot when we were leaving, lone male inside, clearly gawking at my wife/kids as he crept by. I watched him continue through the lot, ominously slowly, then exit the park and get on the highway (by that time we were well behind him). I realize I am more sensitive/paranoid today than, say, a week ago, but the possibility is surely there. And FTR, that beach is at George Wyth State Park, where the town next to us borders the next town over, so its not somewhere the girls would have ridden their bikes. They wouldn't be there without someone who could drive them. If they were spotted there/followed, the perp would have to have kept up on a 4-laned divided highway as they left. Not impossible, but less-likely.
I remember this case very well. I was about Johnny's age, and had a paper route at the time. It was very frightening for me and my parents - our paper gave us whistles and flashlights, taught us stranger safety, etc. I've continued to follow his case and have read his mother's account of what has transpired since, and it is incredibly creepy, and for some reason I remember there being some connection to a pedo-ring in Nebraska where the prosecutor suddenly went missing, and to the Sandusky case. I'm not sure if they were connected, or reports were comparing the cases. The point is, these sick people have a network in this country. It is scary, creepy, and maddening.