I disagree with your last sentence, Cecil.
OK, since no ground rules were discussed before the game, and since there is no physical boundary (line, fence, other barrier such as tree line, etc.) to the field, then what would you have called had there NOT been a game going on on the other field and no one other than a player had picked up the ball?
"Inside the park" HR, right?
This is spectator interference, where the spectator has entered the "field of play". Dead ball, and runners placed according to umpire judgement. Since she was already home, run scores. ASA 8-5-L.
In the "coulda, shoulda, oughta" category, the PU, seeing this layout, should have gotten the ground rules established before the game.
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Tom
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