Return to Witherhelm

I am running my first session of Dungeons and Dragons since my brain injury, which is a little scary. I am somewhat confident things won't go completely off the rails in a boring way.  All the main NPCs were killed in battle and the entire world as the PCs know it has descended into anarchy.

So, the party is going to raid a wizard's tower. A few short weeks ago they saw this wizard take a fireball to the face and fall out of the sky. The halfling rifled through his corpse. Now they are heading to his house to continue looting.

The wizard's tower is in the middle of the biggest known city. Where two of the characters are from. I have done very minimal prep on this city and the characters in my campaign have very minimal backstory (On average we have one death every session so why bother).

So, what happens if the PCs want to go to a bar or speak with their old friend or visit their dad or whatever? There is no info about the characters or the city really.

So here's the rule:  Anything the characters say about a connection they have in the city can be true. They just have to pass a charisma check. There will be modifiers for more powerful potential patrons.

Here are the modifiers:
Regular shmoe  0 (artisans bartenders etc.)
Important schmoe -2 (local politicians, fences, bookies, notable lotharios)
Shmoe who would be worth more than 10,000gp -4 (and an additional -4 for each 10kgp)
person with class levels -1 for every level