My brain attached itself to a "Spelljammer" type Traveller setting.
For those who don't know, Spelljammer was an AD&D setting that
connected all their settings via a fantastic cosmology based on
crystal spheres that held systems and an ether like substance that
flowed in currents between them.
Right now, I'm looking at something similar - magical sailing ships
traveling between systems on ether currents, with the ether currents
stacked in layers that occasionally connect (thus allowing 3d space to
be shown as a series of 2d maps).
Right now, I'm trying to figure out a mapping system that allows for
random generation of systems and currents that doesn't create a mess.
Currently (hah!), I know I want systems on 8+, but the currents are a
bit messy - I have three possibilities:
1: roll for currents first - direction of flow, length, and travel
time, splits, if it goes between layers, then roll systems with
off-current hexes having a penalty.
2: roll systems first, roll for current off each hex face, then
length, travel time, splits, etc.
3: roll systems first, then connect every system (not sure my tables
for that yet) with a current and roll travel time for each.