Against a fish, this is probably just a call.
However, I am bit unsure about constructing our betting range on the turn. I would expect that we are betting strong Kx, maybe like K8+ for value. As a bluff every single gutshot/straight draw. However, can we go much looser and betting with naked hands like 74s or so? Just for the sake of exploitation. Since this card might be perceived as a scared one, it should be just fine, shouldnt it?
We are checking back the turn with weaker Kx and all weaker pairs, A-highs and some naked bluffs and mixing it up with e.g. KK,K9 to stay protected right? Well, then getting to the river with this range, how should are calling range looks like? Do we call every paired hand and some A-highs which are the best in terms of equity against his range?

My only concern is that the vast majority of our turn checking range does not beat any portion from villains vbetting range. So then its probably indifferent whether we are holding 77 or AQ on the river, right?
Btw are we calling this river against a reg?: