A small person-only gate is found to the left of the main (drivable) gate. It is open to the public more often than not, regardless if the main gate is closed/ locked. If arriving outside of the "normal" operating hours, climbers should call the school's number provided on this website (937-599-3010) in advance, to verify the person-only gate will still be open.
It's worth mentioning there are actually two gates, one specifically for walk-ins only, so that a highpointer doesn't get upset or worried if the main (drivable) gate is closed.
In example, I called in advance of this past weekend. The main gate was supposed to be open on Saturday, but wasn't. Nobody was around. At least when I called/ double-checked in advance, the school just happened to also mention the walk-in only gate. This HP Summitpost page did not reference it, and the walk-in gate is not immediately noticeable. I think the walk-in only gate (to the left of the main gate) should be mentioned, just in case of a situation like what I had (where things were supposed to be a certain way but ended up differently).