If there is a long line:
Skip the dump and just roll
If there is a short line:
Roll up, connect sewer hose, dump, close it up and roll
No line:
Use levelers to tilt trailer toward drain. Connect sewer hose.
Pull Black then connect water hose for flush.
Pull grey start black flush.
Close black and let fill about 5 minutes (don't get distracted)
Open black again.... turn off flush hose and put away. (possibly repeat fill/flush)
Allow extra time for black and grey to get down to a very slow trickle.
Move hose to galley and wait again.
Put stuff away. Put levelers away. Roll.
If someone pulls up behind while in process revert to second list.