...Luna, Mantis, Thor, Kang, Century (was that his name?), Wanda looking like Wanda again, the little boy who kept appearing to Crystal and Pierto...the strange door in the basement...yowza. It had everything.
Tuk the Caveboy was going to be linked to the Inhumans by Roger Stern in his MARVEL UNIVERSE series, but alas, it never came to pass. That way, Tuk would have likely been the Tuc seen in the Crossing. Of course, there would have to be some time travel involved, placing Crystal (and possibly the father) in the past circa caveman days, where she would have perished at the hands of other, more violent cavemen (from what I read about Tuk the Caveboy's past, his mother was killed that way). Poor Crystal....that would have been a horrible way for her to go, stuck and murdered in the past.
That strange door in the basement was a great mystery, having started in AVENGERS #375 when Ute the Watcher (from the Proctor story) inadvertantly replaced the ruined mansion with Kang's alternate reality one. Ah, the Crossing....