Deso at 20k is a perfect for beginners. Lower than that will get more technical. I've taken a lot of newbie boaters down Deso at different levels and everyone were fine. Scout the obvious rapids (Steer ridge, Joe Hatch, Coal creek) and explain the runs to the newbies. Once they see your lines it will be easy to follow. Explain the must make pulls, the tongue and keeping the bow down current. People learn quick, especially the ones who pay attention
Have the more experience boat run Joe Hatch and park in the eddy at the bottom, then run a boat with all the kids. Have the bottom boat act as safety. Joe Hatch is too fun for kids to walk it. I've had my son run it at 6 and 7 years of age with me.
I will be one day behind you on Deso, so I can pick up your yard sale if it happens lol.