Is Qassiarsuk any more interesting than Narsarsuaq (or any of the other destinations on the trip)? I have walked through them with Google and they all seem pretty much the same to me in terms of their street scenes.
I'm assuming that Signal Hill is the hill that's at the end of the wiggly road show on Google, opposite the airport (it isn't named)
If it is, for comparison that's 50% further and 100% higher than the walk to Ilulissat ice fjord. So if one can manage to walk to Signal Hill, the Ice Fjord is a breeze (as long as I have sussed the tender landing points correctly).
I have looked at the Ice Fjord Museum website and yes, you do have to pay, and booking is recommended (limited to 100/150 people at a time). But I'm assuming that's just to go inside the museum, not to be allowed to walk the boardwalk. I can take my chance of going inside the museum - though I probably will get around to making a booking before I leave.