Yes you can at sites near most of the parks.
Yes, always reserve a spot for camping at the park ahead of time. You can check for electric availability and reserve individual sites here: https://reserveohio.com/OhioCampWeb/Facilities/SearchViewUnitAvailabity.aspx
Yes. Hocking hills state park has camping.
Yes
I'm also pretty sure I saw tent sites with electric.
Pretty sure ypu can
We saw several people that had only tents at electric sites.
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