Re: 2 pair on a scary board.
 

Aces up and sets should be scared as well. I dont think its such a clear valuebet tho I agree that he would have bet a flush and a straight.

Without a read I would just check it

Re: 2 pair on a scary board.
 

Can't think of many hands that you beat here that call a river bet. Looks like his hand is strong, but he's afraid that you have a Queen. Certainly he can't have a hand like 88 unless he's very aggressive. So I'd just check expecting to see AK/KJ/AT etc.