Went last year with 12 and 15 year old. The river was unseasonably low and pretty shallow, which would probably be better for smaller kids. It might be a bit too long a trip for your little ones. And once you're in, there's really no way to stop until you get to the end. You might want to wait about three years, at 10 and 6 years old. We went during the week. Weekends are mainly floating parties with lots of drinking and debauchery. Definitely NOT a little kid thing on weekends. Lot of fun, though, if you're into that sort of thing (did that 20 years ago PC, Pre-Children). Having said this, I never did it with little kids, so maybe someone else has some better experience with that age range.