Though her wings will allow her to bypass most obstacles on her pass, Rem knows that catching up to the constables is still a matter of keeping a good enough pace. Still, unless something should go horribly awry, she is confident that her new godly stamina will allow her to cross the distance with no effort.
Starislav, meanwhile, considers the situation and realizes that with his horse and his own powers of endurance, he should be able to make it with no problems whatsoever.
Rem's wings do not allow her to autosucceed, but since they allow her to take a much more direct route she gains a +4 bonus on the check. This means that she would succeed on any result of the die other than a 1. Which would be a major case of awful luck.
I must admit I completely forgot about Starislav's horse. Mostly because we've barely brought it up so far. Does it even have a name? XD
That said, between it and Starislav being bound to the word of Endurance, we can call this an auto success for him.
Come to think of it, he could probably take Rem on horseback with him. >_>