This is totally picky but I don't think The Doctor counts as navigationally challenged in a canonical sense - at least not from what I know of New Who canon. I think the TARDIS goes where it needs to be and it may or may not agree with The Doctor about whether where he's piloting to is the same place he needs to be... it'll take him where he needs to be regardless of steering, pretty much.

Although ... hmm, I guess that's a different type of navigational "challenge" but it's not the same thing as being lost a lot...

Now I'm not sure whether I agree with myself or not!!! :)