Pros
You get to know your community by walking door to door, double-checking addresses, determining the number and type of housing units at each location, mapping missing or changed streets and alleyways. There is a lot of autonomy: it's up to you to optimize your route, plan your day and breaks and figure out how best to accomplish your task of viewing every living unit within your assigned blocks within a reasonable amount of time. You can be a social activist by aggresively looking for homeless and other mostly unnoticed fellow citizens.
Cons
It's outside work, so the weather plays a large part in whether you'll have a difficult or terrific day. You may find yourself occasionally working in higher crime neighborhoods than what you'd ordinarily consider walking around alone in. And just finding a bathroom in a residential area can be a project--unlocked construction site portajohns are a godsend!