Also consider the fact that Von Nyon's route takes him through forest, which will probably add a few more hours on to the trip since he has to navigate around roots and trees and such.
Also, realistically, wouldn't Leventis come back first since he has the shortest patrol route? And shouldn't there be some opportunity for interaction with the trooper in your Omadon? Seems odd to just cover the entire mission in one post, but that's just my opinion.