HI Bruce,
Do not fear...be happy, and be excited!! Don't fret too much about what is in the booklet. I have not seen mine yet (it gets mailed to my team) but as I recall from the last couple years, it mearly speaks of the relative size (large) speed (slower) and mobility of a tandem. But, this RAGBRAI is YOUR ride, and no one elses. You and your family just get out there and have a good time, that is what it is all about. I am sure that you will all do your best, which is all anyone can ask....shoot, that is what I do, and no one has ever complained! The last two years, we have had a tandem on our team...and come to think of it, some of the roadie-types probably didn't like getting passed by a tandem that they have no chance of catching! HEE HEE
But, really, I see no problem with them, you will do just fine. And, having the two kids riding with the parents will help insure the kids have a good time. Personally, I look forward to sharing the road with you and your family. Just keep spinning!!