The phrase, "Totally Runnable", is a way to describe the insane/incredible trails that people run. For example: many of the steep trail sections in the Grand Canyon...totally runnable! Or describing some of the incredibly steep trails (maintained or not) around the Phoenix area...totally runnable!
Depending on where we are in training, health, or even how you feel that day, not every trail is "totally runnable" on every attempt. But it's fun to keep pushing forward... running a few extra miles, climbing a few extra feet of elevation gain... or just having some fun being outside.
See that wall over there? Totally Runnable!