Something else that
Star Trek: Star Charts has inspired me about...and I don't think I want to discuss it on TrekBBS, because "story idea" prohibitions.
Looking at the Known Space map in the second fold-out at the back of that book...we see a 750-lightyear "sphere" with breakout "bubbles" around several stars. We are not focusing on them, but upon the coreward Beta Quadrant side, where the furthest-coreward systems tagged as Federation-affiliated are
Antares - see also
Memory Alpha - and
Eta Lupi AKA
Cerberus.
Looking back to the "core" spaces of the Federation, we see the following systems marked out along its coreward fringes:
Berengaria
Arbazan
Rhaandar/Alpha Indi
Ivor/Eta Scorpii
Norkan/Pi Hydrae
Caldos/Beta Octantis
Zakdorn
First reasonable assumption to propose: there should be networks of routes connecting Antares and Eta Lupi to each other.
(FYI: Celestia suggests the direct-line distance between them is about 160 lightyears. GAIA, JWST et al. may either confirm or correct this.)Second reasonable assumption: there should be networks of routes connecting those two systems to each of the latter group of seven systems as well.
Third reasonable assumption: along those routes established in assumptions one and two, there will be outposts, colonies, starbases, full-member worlds and their holdings, and independent star-nations and
their holdings. Yet to have been documented on any official Trek series.
I don't yet know if any of the fan fictions - text, podcast, video - have covered that part of the Orion Arm. There could be stuff hidden in Archive of Our Own, whose creators have reached these same assumptions.