We played this scenario last night. I changed a few things but kept mostly to the script.
I had to tone down the amount of NPCs otherwise the two warbands would have been hampered.
We had two dwarf warbands searching the bulding to find the Count's Tome as it was rumored to have treasure.
We used Warhammer Quest tiles printed up and glued to black foamcore.
Each warband started out on small rooms on their own corner of a 4 x 6 table
They would roll 2 d6 to see what room the got then would have to roll to see which side teh room would be set up on. This was fun as there were a few dead ends.
I let the warband feell safe at first by letting them find d6 gold and a few random arrows were shot at them from traps, then I brought out some zombies and bats. These two groups proved to be no problem for the dwarfs. This caused me be get Mummies involved and it was good as both warbands dealt pretty well with teh mummies and had some great rolls against them.
We insituted the Warhammer Fantasy rule "look out Sir!". Meaning if a henchmen was at least two squares anywhere he could jump in and take the killing blow and push the Hero out of the way at the last minute. You know something you would see in movies.
I am hoping to get some Warhammer Quest cards so I can utilize them also.
We had to modify when NPCs arrive as it go a bit confusing and hard to keep track of all the different forms of combat.