I'm not really that concerned about Trump winning, to be honest.
What's really going to happen? First, he won't be able to accomplish half of what he's promised. Some of it is totally outside the control of the President (like his talk of changing laws that are state rather than federal or fining Ford for importing). In other situations, he's going to face a hostile congress that will use the opportunity to get on CNN or FOX News soundbites. They're probably already salivating over the prospects of Trump trying to pass something they can rail against.
Second, European politicians will rail against him, as well, and use him to score anti-American brownie points with their populace, but that's the way it's always been. Then, when they need help, they'll still say "America, as a world leader, needs to do something". They'll still talk about being "friends" when it's time to make a deal. It's always going to be that way. Trump being in power won't change that.
I really don't like his attitude and the "at least he's not a politician" is a ridiculous reason to vote for him but, if he wins, I think he'll be largely ineffectual at worst.