Red eyes, croupy noise on inhale, sore throat, irritable. no fever. does this sound like something to treat at home or to see the doc about on monday?

Depends: If you were talking about an adult I would say that it sounds viral and just treat it at home and it should resolve in a week. If not see a doctor. However in a 3 year old there are a few other things to consider. If the child is not eating normally or not playing normally then they should probably be seen by a doctor. Any fever or trouble breathing should also prompt a doctor visit right away