its tough!
a friend of mine who is wealthy and owns 50% of a cattle ranch in idaho spent 6 years trying to get in to retire with his daughter who lives there and about £15k!!
we used to have property there and through investigating with english coupler working there, what my chances were being a gas engineer and also a qualified computer programmer, i was told those type of 'skilled' jobs only go to u.s citizens. the only chance of entry unless you have been 'bought in' to cover a roll, are jobs like pool cleaners and gardeners etc.
in the case of the couple i spoke to, he was u.s fireman and the english wife the gardener.
so, to sum up. marry a yank, get a placement before you go (they have to proove no one in u.s is suitable) or apply for a green card 1-2 years and work from the bottom up!
canada is easier route thoough!