To my understanding, the idea behind the interplanetary transport network is that areas near heavy objects and their Lagrange points are accesible with comparatively little energy, for example one could more easily leave low earth orbit via one of the Earth-Moon Lagrange points.
I'm looking for a feeling about what "little energy" and "long travel times" might mean quantitatively.
Now, I understand there'll be no map of the then possible, ever shifting paths around the solar system - but is there some list of sample missions? (Is that the term?)
The papers I skimmed seemd to be very daunting on the math front. Are there easy rules to guesstimate the $\Delta V$ requirements if a probe hops from e.g. from low Earth orbit to L1 to away from the earth-moon system? With what velocity?