I think betting the river, 300?, and folding to a raise is probably better than inducing a bluff. As played I would have to call.

I think its a fold if he is a good player.
But thats subjective.
I think the opposite, fold if its a bad player.
Exactly. The guy might have had nothing but that doesn't mae him a bad player for betting it. It doesn't matter what he had when he bet it, HU you simply have to make these bets and only good/decent players make them. Only a bad player is guaranteed to actually have the hand here.