I'm mapping out the route that Varric and Harding take in their search for Solas before meeting Rook, because I'm in deep now, and I will share it here.
Under the cut for space and also in case anyone doesn't want logistics spoilers for The Missing.
They start at Skyhold and go alllllll the way north to Tevinter. From there, they start in the Deep Roads under Marnus Pell, then go southeast along the Nocen Sea to Vyrantium.
But on the way to Vyrantium they end up "fighting off bandits in the armael hills" -> "fending off despair demons at the wava river crossing" -> "taking a weeklong diversion to deal with antaam slavers" -> "and spending several days suffering from food poisoning…" so that takes a while I suppose. And also Vyrantium is under siege by the Antaam when they get there.
From Vyrantium they go by boat up the Nocen Sea and through the Ventosus Straits, and then their ship gets wrecked and they somehow make their way to Arlathan Forest.
From Arlathan they go all the way back west to Minrathous.
And all that before Varric and Harding decide to recruit Rook.
For extra funnies, Varric looks like he does in DAI at the start of this, then looks like he does in DAV by the end. So he ages relatively fast is what I'm saying. Sure it could just be art differences, but, lol.