M.Q.
The museums you mentioned, time spent at the local library even if there is no organized story time, but what got me through (and I haven't lived on the UWS in 4 years) was finding a "mommy's group" with similar aged kids. I found one through the Reebok center and the other was organized by a college friend. We rotated what house we would visit. Check your ped office for "mother's luncheon" where for $20 you go to a lunch with a speaker who will discuss some aspect of early childhood development and be with other moms who might have some scoop for you. Our building had a playroom which created an instant "playgroup" as well.