I know that most people seem to think MR was the cause of Dylan's disappearance. But, I have boys and although I know I can't judge Dylan's actions on what my children would do, I do often think that faced with a wait of a few hours, a lot of boys would go out and explore the area nearby rather than sit indoors.
Is it really totally unbelievable to think that Dylan didn't see the fishing pole at the house and that put the idea into his head that he could just kill some time by going over to the lake.... and then perhaps slipped in? Not saying he went fishing, just that he may have gone to have a bit of an explore. Lots of boys love poking about around lakes. And MR did mention a few areas around his house that he said Dylan was familar with and liked to go to.
I know his mum says he wasn't big on fishing..... but then his friends say he was a daredevil, he was outgoing and we know he used to spend hours and hours hanging around the neighbourhood.
He may have taken his backpack with him, already packed with all this clothes etc for a few days away - so that when MR pulled up in his car, Dylan could jump straight in without having to even go back inside the house. So, for me, I do still think that it is a possibility that he did leave the house to go outside for a bit, and that he met with a tragic accident.