A popular idea in the survival circles is the Golden Horde. Post TEOWAWKI, sheeple deprived of food, water, shelter would roam the countryside in ever-growing numbers to devour all in their path like a pack of locusts.
With the Great Depression there was (in theory) guaranteed work on the west coast, which caused large numbers of people to migrate west. Also, most of the larger work projects were out west, as rivers still needed to be damned, bridges built, etc. We don't have such public works projects, there is no shortage of workers for the fields of California. Simply put: there is no location to draw a huge number of people.
In the most likely non-natural disaster we face today, the socio-political-economic collapse of the US of A, we face a long slide rather a precipitous drop. So people will stay with what is familiar, what is comfortable. Most people will stay local, to live and die with family and friends.
Within communities I predict those with mobility, whether motorbikes, horses, or methane powered dune buggies, will roam and loot and steal and pillage. I doubt they would be able to muster farther than 30 miles or so without crossing another pack's turf. I'll steal a term from one of my favorite RPG's and use the term Go-Gangs to describe these groups.
I feel that the vast majority of people will be too weak from hunger and disease to get very far. Especially here in the Northeast, where farms are few and far between, and would already be stripped bare by the locals. Without the strength to traverse rough terrain, anyone on the western side of the Appalachians should be safe from refugees from NY or Boston.
These go-gangs will tend to stay local for a number of reasons. First, they will stay close to their home base for fuel, and the accumulated resources they have gathered. Secondly, as I already mentioned, they will run into other go-gangs in their travel. The most compelling reason for them to stay put is that it's better to reign in hell than serve in heaven. The FedGov might be working in Ohio, why go there when we can rape and pillage here?