This is a complex question. Looking at these two maps of population density, the immediate influx of refugees from a collapse would result in a massive Horde from the Atlantic Seaboard away from the urban centers. Most likely their paths would be West and South, but some smart ones will probably head to Maine.
Any of those states belonging to the Atlantic Seaboard's highly urban areas are the immediate worst:
[link to cache.wists.com
[link to www.mapofusa.net
This means: New York and New Jersey will be the worst states. Many people will flee, and that means poor West Virginia is likely to be in their path. Why? Well I doubt they'll head North or South at first much, but look for a middle path through the country. If they head North, they'll most likely run into other fleeing urban people, ditto that for heading South immediately as they leave the most densely populated areas.
Their flight will likely innundate the less urban areas of their states and cause overflow reactions from Delaware, Massachussets, Connecticut, Rhode Island, etc.
Virginia is likely to be hammered by those fleeing into the perceived tranquility of North Carolina.
Florida while having a warm growing climate, has perpetual issues with drinking water. It's so densely populated in coastal regions. It has such an aging population too. I think it will bedlam for a lot of culturally insensitive reasons to discuss.
Many refugees will die in transit, especially if it happens in Winter. I'd expect major drop offs in the population if they headed into Pennsylvania. Some may head that way since the Great Lakes offers certain drinking water.
Montana and Idaho have long been perceived as safe places. I doubt many refugees get that far, for that means cutting across the Drought areas of the Great Plains.
Things are grim for any agriculture in these states based on rainfall alone unless something dramatically happens in 2013
[link to www.eia.gov
I wouldn't want to be West of the Mississippi in all honesty for that fact alone.