when can i take my baby for a trip? thanks

sorry I can't type chinese now.

I am thinking to have a family trip for a few days. My daughter is 5 and half months old. She is very nice girl, but sometimes she cries when she is tired or bored, so I have been only taking her for a quick trip for now, say 1 or 2 hours, up to 4 hours. I don't want to push her for a long trip before she is ready. When baby is ready for a long trip? Thanks a lot!