If you don't expect to use the points for anything else, then 6000 points and a call to AGR will get you that roundtrip. A lot more starting April, a little less if you have the AGR credit card.
If you're traveling peak hours on Friday and Sunday, you may actually get decent redemption value since the fare could be in the $90 range. Check the prices; you can redeem one way and buy the other. And for this route there are tons of cost-saving options involving commuter trains depending on how much you're willing to inconvenience yourself.