It takes two core operatives, and a covert escort
If they can get him over the border it is about 30 hours worth of driving (which you shouldn't - mixed mode of transport is the safest, and packets and charters don't need ID). That means 2 core drivers, a clean protective detail that has not been near diplomatic service (a number of former soldiers, best Warrant Officers). Add in false identities, measures to mess up biometrics and a number of people running parallel to create interference and confuse the trail and you're in business.
From an operational point of view, if the Swiss want to ship Snowden they have the ability. I just can't see them use the M1 all the way, though :). I suspect the hardest part is getting him as far as Germany, but Putin may be able to help here. I don't think the US would dare interfere with a Putin flight - the man has too much leverage and can cause real trouble.
As a matter of fact, I think the US best ensures that nothing happens to Snowden if this came to pass - the assumption would always be that they were involved, and it would pretty much shut the US access to the EU market - Silicon Valley would lose its ability to sell to EU clients overnight.
Biting the hand that feeds IT
