N.P.
Welcome! I'm not sure which area of SE Portland you are in, but I highly recommend the sunnyside swap shop - it's a co-op play space in the Hawthorne area. Its website is www.sunnysideswapshop.org. It's really cheap ($25/month) and has a big play area with toys for all different age groups. There are also Saturday night get togethers with free performers and other events.
OMSI is another great place to go to, if you are close-in. There are great play spaces for all different ages and I know there are mother's groups that meet there.
Good luck finding a place to connect!