Hey Sj, Mason's Tower isn't a nice
district.
In Sharn: City of Towers, here is the (meager) description of The Broken Anvil, verbatim.
The Broken Anvil Inn: This small tavern with a handful of rooms to rent is carved into a bend in the wall of Mason's Tower. House Ghallandra operates the Inn, and the host is a matronly halfling named Eranna.
But, as you may have read in the message board link, both Mason's Tower and The Broken Anvil are located in Callestan. In the Sharn:CoT guide, this is the description for Callestan.
District Type: Inn District
Buildings: Temples (Olladra, the Traveler), average lodging (35), poor lodging (100), average food (5), poor food (40), upscale trades (2), average trades (35), poor trades (75), upscale services (2), average services (30), poor services (70)
First Impression: The inns and taverns in this district are dark and grimy. Vermin run like water through the streets on a stormy day, including rats that scurry into shadows and foul men and women who study you with avaricious eyes.
Social Class: Lower Class
Just thought you might want a little more information about the place. It has a heavy presence of gang activity. Clan Boromar had the heaviest influence in Callestan (even though The Tyrants and House Tarkanan both conducted business in this district), but over the last two years (assuming your story takes place on the natural 998YK time line), Daask has been posing a significant threat to the Boromar's position in Callestan.
Another note about this place states "
Callestan is the best place to go to find a fence, arrange a burglary, or acquired forged papers."
However, I am adamant that the final say-so of anything in a campaign rests with the DM. If you want it to be different, it's your call.