I went to the American Dream today. As of now, it's just the amusement park, ice rink, and ski area open. The waterpark looks almost ready. I saw one of the buses come in and it was pretty empty. I drove there and the parking lot wasn't that full. Doesn't seem to be enough demand for rail service yet. The other issue is the station location. It's located next to the stadium and is pretty far from the mall entrance. It's odd that they were originally planning to run it daily once the mall opened when it's clearly designed to be used for stadium events only.
I don't think there will be rail service to the mall until NJT has resolved their staffing and equipment shortage issues, and either demand increases to the point where the buses can't keep up, or Triple Five pays NJT to run trains.