I'm partial to Broken Bow, but more specifically, Beavers Bend. All three campgrounds Fern, Buckeye and Cypress have views of the river, Fern is a little higher on the river, and you can reserve @ Buckeye, but not at the other two. Buckeye & Cypress are level with the river.
Great fishing spots along the river. You can rent row boats to fish and lots of birds on the banks of the river. Unbelievable beauty and practically no cell (I got AT&T bars, but as extended service, and they get very stingy with the service and will throttle you - kick you off). But this was a chance to turn everything off and relax in the beautiful surroundings.
I preferred Fern because the sites were so large, but Cypress & Buckeye are probably better laid out and more modern.
