According to the MTA

… ELECTRICAL IMPROVEMENTS Sep 18 – 21 Sep 25 – 28 Oct 2 – 5, Fri 9:45 PM to Mon 1 AM F Trains are replaced by the E between 21 St-Queensbridge and Delancey St/Essex St…
… Travel Alternatives:

E replaces F at 21 St-Queensbridge, Roosevelt Island, Lexington Av/63, 57 St, 47-50 Sts, 42 St-Bryant Pk, 34 St-Herald Sq, 23, 14, B’way-Lafayette Sts, 2 Av, Delancey St….

There is a Roosevelt Island Tram Cabin 20 passenger Covid-19 Social Distancing limit. No answer from Roosevelt Island Operating Corp ( RIOC ) if they will follow the MTA and issue $50 fines for riders refusing to wear a mask.

Here’s the NYC Ferry Roosevelt Island Astoria Route Schedule which now extends to East 90th street on the Upper East Side.

Also, Roosevelt Island has a new transportation option with the recent addition of Citbike docking stations.