I've been thinking about the man that drove them home, and while I think some people will find it 'unorthodox', I understand it. I don't know how close his property was to the perps, but if he was a neighbor, and the perps said that they would be back soon, he may have not wanted to risk waiting for the police. Especially if they had weapons, etc. Maybe guns were mentioned and they just wanted to get the heck out of there. I know the police PROBABLY would have gotten there before the perps got home, but what if they didn't and the perps went to the neighbors house? What if there was a nasty confrontation or shots fired? Plus, there were police all over the girls' hometown, so it's not like it would be hard to find an officer once they got home.
In a situation where there are two dangerous, unpredictable people who could show up at any time, I would probably want to leave too. JMO, though. I mean the girls saw the perps, knew where they lived (so did the man who drove them), so I don't think he thought that they would suddenly point the finger at him as the perp .
Also, I think they gave them watermelon vs a cooked meal because it was quick. I think that they were trying to get the girls out of there ASAP. Being Amish, I'm sure that they don't really eat 'processed' foods, so watermelon may have been the most whole, quick, kid friendly food available.
I read on one articles that they passed the perp's car on the way home and ducked in the back seat, so they didn't have a whole lot of time apparently between leaving the neighbor's house and the perps returning.