I know witches get a lot of respect in Ustalav, but how far does that respect -- and knowledge of a witch's capabilities -- go?
To get to the point, if a small house on chicken legs is seen walking down a main road, will passersby panic or realize it's a powerful witch (and then will they panic again or just nod and give it a respectfully wide berth)?
Would it help if the house was cheerfully decorated, and set up with a front porch with some ordinary-looking person sitting on a bench and acting like a carriage-driver? :)
Are you thinking of Ustalav or Irrisen? Witches are likely to get burnt in the former and are feared and respected (but mostly feared) in the latter.
Actually witches are generally respected in Ustalav, much like wizards are elsewhere. Hedge witches are seen by locals as useful practitioners and town healers. You're definitely right about Irrisen though.
A powerful witch in Ustalav would likely be treated like a powerful wizard in other places. They would definitely get respect, but the rest depends on how they've interacted with the people. If the witch has been a defender of the community and helps people out then they'll be welcome just about anywhere. If the witch keeps to themselves and has eccentric habits they will be thought of as that odd warlock in the woods who doesn't normally cause problems but let's not invite him over for dinner. An evil witch who enslaves, murders, etc. would either be burned at the stake (especially by PC's), appeased like a tyrant, or followed with zeal.
If the witch in question is new in town and is riding her happy chicken hut, she would probably be treated with a mix of curiosity, fear, and respect. The town guard/mayor would want to have a word or two, but they wouldn't immediately grab their torches and pitchforks. Again, this also depends on the town in question. Some are more accepting than others, just like real life.
I now have a weird image stuck in my head of a chain of Chicken Hut mobile food stands wandering through Golarion...
Because small children are to fried chicken what veal is to steak.