Too late to help you before the session, and probably doesn't matter in an intro, but going forward, I'd try to have two skill challenges, each suitable for around five characters. (Same as with having two encounters. You can also have a skill challenge and a combat encounter mixed.)
For example, you have one skill challenge as you listed. The other one is maybe something like concealing the party from the goblins and other denizens of the area, while the tracking goes on. That example is kind of lame, as it is essentially splitting a core idea into two parts mechanically, when they could just as easily overlaps. It is difficult to provide a better example without more context. I will say that if you try to do this, it gets easier and better, very rapidly and naturally.
(If I were doing something like this intro, there would be another, mostly unrelated hook in town, perhaps a thieves guild, a corrupt mayor, or whatever. The second skill challenge would be about that. )
This is also handy for enforcing failure. If you have a skill challenge sufficient for 10 characters, it almost has to be fairly large. That means failure can be quite nasty, if pushed to its logical conclusion. I use "partial failures" in skill challenges as well, to mitigate this. But its easier to be hardcore with the results of one skill challenge if the challenge is appropriate for half the party.