There is an access roadway showing on the N bound side of Route 1 from North Street that appears to end at Hulmeville Road. Can you explain how this is intended to work / the purpose?

That was just re-establishing the connection of North Street, so it does not end in a cul-de-sac or a dead end. With the removal of the service road down below North Street, adjacent to Route 1, that is just an extension of North Street to connect it to Hulmeville Road and maintain that connectivity from Myrtle Avenue to Hulmeville Road.