Collison Par 3 over in Marshalltown. That's where I learned from my parents when I was 5. Nice little go around, longest hole is just over 200 yards. I would definitely recommend there.
As for short courses, The Oaks just North of Ames is short, although pretty woody so might not be best for a beginner. There's also a short course out in Colo that has big, open fairways that I would give a shot.
Played Collison back in the mid '60s as a kid. It was a nice course back then. You used to pay at the dentist-owner's house on the way around. Glad to hear it's still going.
Regarding playing only par threes, I always had the kids tee off where I drove it to on par 72 courses. Works out pretty well.