He chuckles at the question. "Not exactly a vacation, but gone awry, definitely. Got left for dead and burnt out my vortex manipulator--" he taps the leather strap around his left wrist "--trying to find my friends. I found them both in the end, though it took a good long while."
It's the short, sanitised version he gives to people he's just met, people who don't need to know the Doctor ran away from him rather than leaving him for dead, and that it took almost a century and a half before he found him again.
"Oh, but jumping systems, that's pretty good. It's way more than twenty-first century Earth has got, although obviously there are other races that have. It's just getting a hold of them to hitch a lift off-world that's the fun part!"
A movement nearby catches his attention - a bot approaching with a tray of drinks. He grins, and beckons it over. "Hey, you want a drink? I'm parched!"