Nestor leaves the hostel with his servant shortly after sunset. In a back alley (or a stable - some place where he has a minute of quiet), he casts a spell to assume the form of an elderly rigidly fasting pilgrim and puts on appropriate clothing (that his grog bought earlier). His servant is to wait for him with his usual clothes.
Nestor then approaches the alms kitchen of the bishop's palace. He asks for food, water and access to a church - and offers to do a few hours of menial work for it like washing dishes (he is confident that they won't make him work for too long because few people work long after sunset. He also chooses a fragile appearance for himself, because he knows he is not good at hard physical work.)
He tries to talk to palace servants (or overhear them) -- he hopes to learn about the bishop's tastes and reputations from the servants.
If asked who he is he will reply that he is a pilgrim fulfilling a vow to Mary. He will call himself Dimitri.
If all goes well, he returns to the servant and casts another spell over the old one, so he looks like himself again and puts on his normal clothes. He sleeps at the hostel.
he rolls a 5 and a 6 on his spell rolls for assuming another human form. He waits until fatigue is restored before going on.
If anything goes wrong his first defense is a forgetting spell, failing that a sleep spell.
Both the servant and he watch out for people observing them.