Small fighters have no problems travelling long distances as most of them are equipped with hyperspace engines, but the pilots generally can't survive the long trips without food and water. But Jedi have an ability called "Hibernation Trance" that allows them to basically hibernate for long periods of time without have to wake up for eating, etc. They use it for especially long space flights (Luke uses it in the books to travel great distances in his X-Wing). My guess would be Vader set course for the nearest base and went into hibernation. Which would also explain why the Empire didn't just come back and wipe out the rebels with a bunch of Star Destroyers ('cause it took a while for Vader to get back and inform them all of what happened, leaving enough time for the rebels to relocate to Hoth). Although I have no idea if there is an official story on the matter.
As an interesting sidenote, Grand Moff Tarkin (the guy who was in charge of the Death Star, the "Escape, in our moment of triumph? I think you overestimate their chances" guy) ranked higher than Darth Vader, so the destruction of the Death Star led to Vader becoming the leader of the fleet, and 2nd in command only to the Emperor himself.
Yes, I'm a Star Wars geek. So sue me.