When my 2 were at that age, wide open spaces were the best bet -- trails, playgrounds, soccer fields, basket ball courts (without players of course). The beach was tough because one liked the sand and the other the surf. The local children's museum, Natural History Museum, zoo, Wild Animal Park were all very doable during the week when the crowds were low. At these type things we actually faired better without the stroller because then I didn't have to be pushing that and try to manage dds at the same time (because they never wanted to be in it). I could keep up with dds without the burden of the stroller. We just didn't stay very long and would have frequent stops. We also have a wonderful botanical garden in town that is low key trails and an enclosed children's garden where we spent a lot of time.
Storytimes were actually THE WORST for us. I could not keep them sitting and they'd be crawling all over everyone, grubbing snacks off the floor, and interested in everything in the place except the person reading the stories. I tried a few times but it was never fun. They were at least 2.5 before storytimes worked for us.
And the leashes. I bought them with high expectations of expanded freedom. Tried them once and it was a bust. It was much harder walking while trying to hang onto the leashes, keeping dds untangled, fighting the pull of one while the other dawdled. I kept the leashes because I could still see how they may be useful in an airport or shopping, etc, but the need never arose.