/diy/ - Do It Yourself

Does anybody have any experience with building public goods outside of their property? I wanted to build a pullup/dip bar in my friend's yard and use that as evidence I could build it for the town parks and rec department. I'd like to build in our public park, so anyone can work out, and I'm going to be buying all the materials since I see this as charity work.
Does this seem like a reasonable plan or does anyone have any suggestions?
The image is similar to what I had in mind.