I know this has been discussed before, but I didn't want to open an already closed post.
Anywho, during real-world operations, the pilots and crew will always board the aircraft prior to the passengers, most of the time 10-20 minutes before boarding. Currently, they are tied together and pax begin boarding right away.
I fuel planes for my day job and when there is a crew change, the pilots arrive at the aircraft well ahead of the passengers for obvious reasons. I think, to increase an already immersive and realistic addon, the pilots and crew should board separately from the passengers.