Coming up with a definitive set of Nevernever travel rules is almost moot, considering that the fiction leaves it as very plot-sensitive how easy or hard it is to pass through a given Way. That said, have any GMs formulated homebrew rules about how to handle passing through the Dresdenverse's equivalent of the Astral Plane?
I myself have been handling it by the seat of my pants. One Nevernever jaunt dropped the players into a breathable Nevernever "ocean" filled with distant but circling predatory shapes, and alien whalesong - the only objective was simply to escape the authorities, so they just had to end up somewhere else in San Francisco. It was a complete surprise to me when they suggested it (I was anticipating they would buy some time by hexing the emergency vehicle that was there to take away their mindwarped friend before they had a chance to do a counterspell, but they took her into the NN instead).
Another Nevernever trip to meet the Archive on Easter Island was handled as an extended challenge, as they were hounded through the Nevernever by a Summer Court posse (San Francisco is technically "theirs" inasmuch as any city can be claimed by a Fairy Court, and one of the players has a Winter Court artifact).
How have other folks been handling this?
Are you finding that trips to the Nevernever come up on the spur of the moment, or are you fairly good about anticipating and planning for them?
Have you developed an "Encounter Table" of sorts for random NN jaunts?
Have you definitely mapped the different Ways available in your game City?
Are you tracking the rips in the fabric of reality in case opening their own Ways comes back to bite the players?
Edit:
Also, I have been handling opening portals to the Nevernever as a Thaumaturgy effect which the players can usually do without any preparation (the designated Nevernever doorman has Lore +4, and an Enchanted Item which boosts this, so most well-chosen locations are going to have a thin enough barrier for them to open), but I've been letting it happen in an exchange, rather than in minutes, so I've really been running it as Evocation.
Does anyone run Woldwalking as an Evocation effect? Do folks use one or the other depending on circumstances?