I'm not a proper historian whatsoever, I just remember this from when I was at school. The government would give free land to homesteaders, and even more land if you cultivated it and planted trees. There was obvious trouble with law and order, hence all the wild west films, as groups of vigilantes were often more enforcing than the state sheriff. Forts were dotted along many of the miner trails, to defend travelers from native Americans. The California gold rush brought huge amounts of people West, which greatly benefited the USA government, without costing them anything. The Mormon movement West displayed how communities were self governed, not just in Salt Lake city, but their many other towns they set up along there way. There may have been little government help to the Mormons due to public opposition, or because the US government just didn't really help with any group.

I think the government encouraged the mass movement of people, by implementing motives to go west, but there support other than that was limited.

I have probably got most of that wrong, and don't know any specifics, but I hope that gives you a very vague idea. And sorry for huge amount of grammar and spelling mistakes, I'll try and correct them but will defiantly miss a few.