Agreed with Ay. There are a ton of 'gaps' in the Haarlock storyline (it doesn't run straight though, and is very winding). It lets you add a bunch of material to the downtime.
If I might make a suggestion:
Edge of Darkness is a great prep to any group, especially ones that aren't familiar with the setting or rules (it's mostly investigative). I find it also helps set the overall mood of the setting. Shattered Hope is a great introduction to the rules, and also serves as a fun adventure for beginning characters.
Purge the Unclean is a simply amazing book, and well worth a potential usage of the adventures in it.