Why on Earth would we have two hours?Yeah, it's definitely feasible for us to take out a Karak on our own in 1-2 hours /s
Maximum speed for the expedition is 4 miles an hour for ten hours- 40 miles.
Mathilde travels at 25 miles an hour on a shadow steed, and can go for a long time. They could leave go for several days and we would be caught up in a flash.