I'm currently in the US on an E3, and while it is true that it is rather hard to get credit/insurance/a car when you first arrive, it does get easier. The trick is to start building your credit history from day 1: get a couple of secured credit cards and keep them paid. It'll take a few months for your credit history to even show up, and over a year for it to be any good, but it will happen. Credit Karma and Credit Inform (which you get for free with a Capital One secured card) are good tools for tracking your progress.

You should definitely have a decent amount of savings when you move over though, to offset the lack of credit.