You could also dig up Lost Soul's thread 'Sandboxing in the Nentir Vale'. He did some fun stuff woth KotS.
I stole a lot of his ideas.
I used the FRealms version (from one of the first 4e DDI mags). Basically, the Dwarf getting rich at new General Store is in with Kalarel. He has a cult church down under his store which quite a few town members attend.
I placed a NPC Paladin in the tavern brooding over his untouched wine. If the PCs bring him 'Bahamut's Mirror' from burial site (Doven sends them to paladin once rescued), he will put them to the test and possibly join the PCs. I made a challenge for the PCs in order to demonstrate it was Bahamut's will he aid them, with a good old fashioned arm wrestle and all. The paladin was intent on restoring his orders lost honour and clean the name stained by the leader who fell to the dark powers in the Keep. until they bring the mirror he refuses to talk to anyone.
My Pcs gained his favour after bringing the mirror and he accompanied them to fight Iron Tooth. Iron Tooth killed him however. The PCs returned his body to town and I had the mayor throw a massive party for them, all townsfolk attending, and he took care of the body. I had the mayor being bribed by the Dwarf and the Elf Ranger, as they had stolen his prized stallion, his life's passion, which the elf kept at her hut in forest.
That night, I had this Dwarf send out his dark servants to attempt to steal the mirror retrieved from the burial site but they had set a trap for such an event by switching rooms. This led them to the dwarf when they captured the servant. I then had the Dwarf negotiate with them ... down below his shop in the cult church. The offer was: Stay out of things, don't get involved. Twice the gold offered as a reward to get involved, but they had to swear it laying a hand upon the dark altar. They refused and a battle ensued against the Dwarf ... ah Bairwin, that was his name. And who should appear but the now undead Paladin who had aided them. Bairwin had been busy with his body since they handed it over to the mayor. Meanwhile the Elf (Nirae?) set the shop on fire, sending black smoke and flames down into the church and locking the doors. They luckily found the secret entrance and escaped wit Bairwin as a prisoner.
The Keep I added a random chart of spooky effects that occured at each short rest if a PC failed an Insight check of the relevant DC, depending on the effect rolled. This made resting difficult and ruled sleeping in the keep out of the question unless they found a haven (Room behind invisible wall). It added loads of ambience to the whole thing. If a PC over came the spooks 3 times in a row s/he became immune. I also swapped out loads of HGobs for dark servants and things and erased most of the east wing of lvl 1 (with Kruthiks etc.). We didn't get much further, as they'd left Bariwin tied up outside. A Kobold that had escaped them outside the entrance, found him and released him. Bairwin took revenge, (they hadn't been kind to him) went down into the keep and organised a hunt. The PCs were unwisely attempting to rest in the keep and Bairwin with a team of guard drakes found them and killed them.
There is loads you can do with this module if you think of it as the bones. You need to put in the organs that bring it to life, add the flesh and sinew to get it moving, and stretch skin over it so it easy easy on the senses.
