By request, here's the home of the 1869 Cincnnati Red Stockings, Lincoln Park Grounds (aka Union Grounds). There's a bunch of the kind of information and imagery that I'd normally put in a post (and a lot more!)
in this thread started by DrDoom, so I'll keep this relatively short.
Google Drive link to Lincoln Park Grounds
There are no period atlases showing the structures and only relatively rudimentary sketches of the grandstand that date to the relevant period, along with artist's depictions from the modern day. So, this is something of an amalgamation/best guess from those. The same can be said of the dimensions of the field. I took the background from a town nearby Cincinnati, so the topography isn't right, but hopefully it gives something of a flavor of the grassy/open area that (I think) the park was placed in. Period reports do talk about people bringing red handkerchiefs etc. to wave around, so I tried to lean a bit into red paint and flags.
Since this was a request, there could be a version 2 depending on how satisfied they are, and perhaps more versions depending on how adept I am at accommodating them.
I expect to be in a bit of a travel lull and my simulation is nearing the end of its season, so I might be able to get a few more parks done in relatively short order. I'd expect Messer Street to be the next one I tackle, unless something else grabs me first...