I've updated the geocoordinates to be more accurate, and the written instructions were good, too. I parked in the City Gospel Mission parking lot. There's a little brick wall memorial with an info plaque to Crosley Field, and then behind the building, down the alley to the right, the location of home plate is painted onto the ground. The memorial thing was unexpected and really cool, but the home plate location is just paint on the ground. I personally love weird photo ops like this!
The way to visit is to take a guided, ranger-led tour, which they offer between December and April
This is a home, and on private property, but you can check it out from the street. Definitely quirky, and cool to think that it was one man's passion project.
Tours are Wednesdays at noon and 1 pm and on Saturdays at noon and 1pm. Buy tickets online in advance.
Dogs are allowed on the boardwalk but not the beach!
Tours are free, but book a time online in advance!
They're open daily from 9am to 5:30pm May-Oct and on weekends in November. Book tours days in advance if possible, they fill up fast.
Tours are on weekends between 10am and 2pm. No reservation required. They ask that you make a small donation.
Be aware that it's closed during the off season. Check online if you're planning to visit in the late fall/ winter/early spring.
FYI, clothing optional.