I posted this on the original thread at
http://www.enworld.org/forum/showthread.php?t=234265 but I'll post it here since I'm still running H1 for my group and the hooks I used were better for them simply because I had more control of them.
[sblock=Plot Hooks]
I twisted H1, a lot, to suit my tastes. Kalarel was female and Ninaran, the ranger was male. I don't know if I spelled those names correctly so forgive me if I butchered them. It made for some fun at the game table, specially because I started that adventure with the PCs helping out a caravan, in which Kalarel was a passenger. This was an unrelated side-trek as part of the setup for KotS.
I don't like the idea of the Bloodreavers being the pervasive enemy between the two adventures. I mean, it is a good link but in my opinion it does not do enough to link the two adventures. So In my game I'm planning on having Paldemar be Kalarel's former mentor. After Kalarel started rising in power he saw her more as a threat and decided to get rid of her. He sent her to Shadowfell Keep, knowing full well that the ritual she would try to perform would probably kill her.
I'll have to make some other changes to both adventures but I like that "hook" better.
In H2 Paldemar is a follower of Vecna, though this is a secret. My reasoning for him sending Kalarel to Shadowfell has to do with being able to siphon power from the rift in Shadowfell and using it for his "infernal machine", with which he plans to dispose of the Mages of Saruun. Of course this is a blatant lie but if Kalarel succeeds he'll just kill her at the same time that he disposes of the other mages and if she fails, then no harm done. This also feeds into the hooks for the follow-on adventure H3

yramid of Shadows.[/sblock]