[Cerek the Barbaric]

I also entered Watcher's Keep while still in SoA (in fact, I've never played ToB yet). But I waited until my party had completed the first part of Suldenesser before going, so All of my party was over 20th level.

Because of that, the first couple of levels weren't too tough, but Level 3 and beyond was still pretty challenging (I had to cheat and use a walkthrough to find my way through the maze because I also just kept going in circles). My BIGGEST challenge was - of course - Demagorgon.

My PC was Wizard Slayer/Thief. I didn't Dual until I had gotten a couple of the fighter HLA's and I naturally took "Use Any Item" as my first thief HLA.

The rest of the party consisted of Minsc, Imoen, Jaheira (who REALLY kicked some serious butt with her spells and HLA's)and Jan.

The fight with Demagorgon took several reloads to complete. I finally defeated by setting as many traps as my PC could. Since the traps go off before pre-cast spells, I was able to prevent a lot of Demagorgons protections from going up. THAT made it MUCH easier to beat him with the spells from MY group.

Watcher's Keep is very challenging, but it CAN be beaten by an SoA party.