Rhinebeck is great day out. Saturday and Sunday are two different
shows. Both are great, so you should really see both. I have been
going once or twice a year for about 4 years now. My now 6 year old
daughter has always loved it. We usually bring a wagon with a cooler
and folding chairs. The best place to sit is north of the announcers
stand on the hill, all the way in the rear. This provide both a great
view and usually by show time you are actually sitting in the shade.

Spend some time before and after the show looking at the aircraft. It
is usually a lot of fun to talk with the pilots afterwards. They are
generally very eager to talk about their planes and their flying.

You should also spend some time in the museum up the hill. But, I
have found that to be a bit much for small children. The planes that
make noise and fly are great fun, but the ones that just sit there
don't get the kids attention.