I got to the Severed Hand in IWD2 twice, Dragon's Eye time-warp place once, and the goblin fortress several times. In IWD1 I don't think I ever went past that Ice Dungeon place with the trolls nearby...the place you can just walk straight across and skip an entire chapter. Chapter 5 or 6 or something.
've played through the first two thirds of these games so many times it isn't funny, and as any experienced IE gamer will know, once you've got the combat system down nothing is a challenge so it makes it even harder to commit to going the whole nine yards.