River is an easy bet, however I think something like $10-$15 is more in line as you want weaker hands to look you up. I don't see a sudden need to want to play a big pot here. Checking is bad because hands with showdown value will often check behind when they would have called a value bet. No way you fold to the river raise getting around 4:1 on your call, as the only hand that beats you is AK. I'm almost tempted to just shove the rest in.