There are many wonderful Children's Museums that also have spaces for the
toddlers, who are often overwhelmed by the bigger kids and their
enthusium.  One that comes to mind is the San Jose Discovery Museum, in
San Jose CA - they have a room set up for the little ones and their
parents, there are toys and exhibits that are age approiate and the kids
over 5 can't come in so the little ones don't get pushed away from the
toys (at least not as often:) )

There are also materials and resources for parents in the room.  I was
there on a visit in May and it looked like several of the kids there come
on a regular basis, they seemed to know the staff and the other kids.
Which to me was a good sign that the locals thought the room was a great
place to go.

Good Luck
Chrissie Devinney
Mom to an almost 1 year old - ps the definition of toddler that I am
familiar with is a child who is walking (or toddling)  that is still in
diapers or is not yet in school.