I'm finding that hardcore Whovians tend to be rather brilliant snoops. To whit: a tiny little CV for Doctor Who line producer David Mason was found buried online and mined for this interesting info:
DOCTOR WHO X1.2 Director: TBA
USA Location Shoot Producer: Marcus Wilson
So, it would seem that the good Doctor is headed to the US for… something. About time too, I think. Were Russell T. Davies still behind the wheel I'd suspect an imminent crossover with the newly-Americanised Torchwood but he isn't, so…
Well, I wasn't expecting any kind of crossover between Moffat's Doctor eleven and the work of RTD, but the current series of The Sarah Jane Adventures has proven me wrong.
Still, there's a world of difference between the Doctor dropping by to cameo in a spin-off and the characters of such a spin-off invading the main series, so I'm thinking that whatever reason the bow-tied Timelord has for crossing the Atlantic is his own and won't have anything to do with any other show.
Kudos to Chuck Foster for the detective work.