Fairly soon. It is just the calm before the storm and the roads are still safe even in 'our' past. Unkle has The Thing, which is different than I remember, but I have a feeling that it will be far safer with him for now. I would be too tempted to advance the story if I were to have it in my possession now.
They will get involved again, since of course, they are too inquisitive not to. And you being their 'chief spy' on me will ensure that their curiosity about our quest will continue to grow. I suppose I will still have to act surprised when you conspirators are unmasked but that shouldn't be too difficult. I do not think this journey south looking for the palantir with Aragorn will change too much of our future.