Offering life experiences is important to increase your child's vocabulary.  Remember that socialization and independence need to be the focus.  Talk about the trip ahead of time - use a picture schedule or story if it is helpful.  Then, talk during the trip to explain what is going on.  During the trip, take pictures.  Encourage your child to make choices about what to do next, talk to the other children at the event, and do as much on his/her own as possible.  After, make a social story about the trip using the pictures and read it with your child to work on recall and shared experiences.  Each child is unique and parents know which experiences are right for their child.