In a comment on the same post, John Harper said: “The classic D&D method gives the PCs the choice to drop food and/or gold pieces to distract or delay pursuers, so it’s not just ‘compare movement speeds.’“
I think that would be an even simpler alternative. In the days where the dungeon expedition was mostly a question of logistics (rations, torches and oil going down and treasure coming up) it makes sense to make the escape a question of resources spent. Forget about chase rules, so to speak.
I guess the number of hit-dice pursuing you should indicate how much you need to drop: a daily ration or 100 gold per hit die squared, perhaps?
– AlexSchroeder 2014-01-13 10:02 UTC