If we seem insular, Brandon, I think it's because of our focus on the completion of this game as a goal and not because of a lack of exposure to, or interest in, other adventure games. As far as Sierra goes, I love Police Quest just as much as King's Quest. To answer you more specifically, I think Space Quest is a great series and I've gotten a lot of laughs from it.
I believe it takes a certain type of personality to really appreciate Space Quest the way you do. It is a personality that the Two Guys from Andromeda (three if you include Josh Mandel) have taken from themselves and infused into their games. Likewise, you and other fans have taken that personality from within yourselves and are infusing it into your own games, starting with Replicated and The Lost Chapter.
The type of personality I talk about may be slightly alien to me, but the important thing is that I believe your games reach others who really do get it just like you did. In my mind, that's what fangames are all about.