My Son has been fishing and crabbing with me since he was 2. At first we fished a pond near a playground. He started boat fishing with me when he was 4. Bottom fishing with a lot of action is the way to go. Trolling at a young age might be difficult. You know how boring it can be to us. Have some toys or activities for them to fight boredom. As Skip said, most kids don't like getting up before the sun comes up. Good luck.They make great fishing and hunting partners and it only gets better with age............until puberty kicks in
........Gary