Never leading river as played, i think we can remove underfulls since he most likely would have played set of 5s/4s aggressively on wet board here... That leaves only busted draws and you said he's not tricky so weak-lead to induce large bluff is out of the question.

Check to induce bluff.

Checking usually leads to a weak/give-up check behind by vill in these spots. Depending on that frequency from vill, we're losing value by not leading (for a call or to induce).

Min 3 bet the turn is an option. He is likely to call with all his draws.