The “right” way to do Dunes is to bike camp there. Ride your bike to your nearest train that gets you to the loop and take the southshore train (or do the whole thing by bike).
You can do a similar trip to Zion up north which is even easier from the Northside. You can be sleeping in a hammock walking distance to the water in either direction pretty trivially.
I’m less familiar with the western suburbs version but have friends that do starved rock this way.
I don’t think it invalidates your point and the time it takes to get to somewhere “outdoors” is actually my biggest complaint about the area but both of those parks are definitely doable after work… so long as you stay the night.
Here is a link to a group that does those trips as tours and does advocacy: https://www.oofd.org/