I do have a sonic (my brother does, cause I got it for him :D), so maybe that will help :D
Well, some controversial interpretations of the multiverse would suggest that the increasing divergence of physical laws from ours would suggest that some fictional characters would actually exist (no matter how improbable they are), so somewhere the Doctor could exist.
On a more realistic level, the world wouldn't have welcomed the show back unless it was based on a person they needed. At the end of the day, the Doctor isn't a great scientist, lonely god or the last of the Timelords; he is that one person that is just so far above it all that he just finds his own category. That kind of man MIGHT exist.
Forming LINDA "London Investigation 'N' Detective Agency"
Providing No Abzorbaloff's join
The second one was what I thought of the moment I saw the discussion title XD
Honestly, I will be doing all of these now. I'm surprised I haven't been... But definitely the Donna strategy.
- Find Torchwood?
- Go into EVERY blue box that you find.
- Anyone can be the Doctor, ALWAYS be on the the look for him.
And that is all I can think of at the moment.. :/
While I wouldn't recommend the self-infection strategy, as the Doctor can't save everyone, keeping alert for any strange door on an object would be of help. For example if you see a "door" open on a bookcase, etc. You never know when that chamelon circuit will be fixed in a future incarnation, even if it is just a moment to show off, or he's incongnito while visiting this time-frame.
I would also look around for couples holding hands and running -- and actually being chased by something that looks like it belongs on a movie set. The question remains should your strategy be to back-track where they started running from, or follow along to help?