I float the North Fork several weeks of the year. I do a week at the end of March, a week around the 1st of July, and a week in September. It may be my favorite river- but I'm partial to fly fishing for wild trout. As for Gibbs, I think you are referring the takeout at Gibbs Bridge, which is at the inlet to Buff Bill Rez. I float the N.Fork from Pahashka down, and the Shoshone from the rodeo grounds to the take out off the Powell Hwy. I have a 10yr old, and he has been down that river starting at age 3, and my wife rows most of the time the fishing is good. The crux to your boating fun will have more to do with finding the launches and take outs, shuttling, camping, and bear safety. Tim Wade's fly shop could arrange a shuttle. I take a bike along and do the shuttle myself.
Email me if you would like some more info: [email protected]