To clarify, I'm wondering not just on the general consensus, but about the extra room that opened up, what happened to the jobs people left behind, the food stores, things like that.
I'm guessing many criminals headed west to escape prosecution, so how did the eastern law men deal with that? Was it just putting out bounties, or was there some other process?
I'm afraid that I don't know much about this particular topic, put a good place to look would be in the works of Alexis de Tocqueville. He was a French political thinker who traveled throughout the United States in the first half of the 1800s. His book Democracy in America discussed the evolution of Jacksonian democracy and the American market revolution.
The book is not yet out, but Mark A. Eifler, an Oregon historian, is working on one about this subject. He has researched correspondence between those who stayed East and those who went West, in some cases having found the letters each way, and has some great stories about it. I think it should be out some time in the next few years.