Muni Credit Assessment Case Study

I'm early in the interview process at a major AM (i.e. Nuveen, Invesco, PIMCO, etc.) for a municipal credit research position. Part of the interview process involves preparing a 1-page credit assessment on a lower-rated general obligation credit (i.e. Puerto Rico, Detroit, Chicago, etc.). 

What are some major credit considerations I should be looking for in my review? I have access to an offering document and rating agency reports.

Thanks!