The abstract campaign system wasn't grabbing me so I found an actual 1870 map (in the public domain) of the South Pacific and drew us all up a campaign map. After about the third revision of the campaign system, we've come up with this:
The 'Eyrie' is the special scientific base we all fought over in the Epic 4 vs all multiplayer, earlier this week. Five territories border onto it (the Coral Sea doesn't) and each faction has one of these each. It produces 1D3 RP per turn and provides a range of scientific benefits, including allowing a ship to mount more than a single shield! The rest of the territories follow this key (see the full campaign rules for more info.)
Town (Large town): gives 1(2) RP and has 'shore leave'; large town also adds 'hospital'
Depot (Repair yard): gives 1(2) RP. Small depot allows you to replace a small squadron for free, large depot allows you to replace a small squadron for free or a medium squadron for free.
Oil Derrick (Refinery): gives 2(3) RP and has 'combustible cargo' for one squadron; Oil Refinery also adds 'experienced engineers' OR 'Sturginium boost' for one squadron.
Pirate Base (Opium Traders): gives 1(d3) RP. Pirate Base gives one small squadron the 'extended range' MAR for free; Opium Traders gives 'opium traders'.
Airfield (Airbase): gives 1(2) RP and provides a TT Wing. Airbase also gives either the 'large fuel tanks' MAR OR Better Engines +2'' move for all TT Wings.
Fleet Base: gives 4 RP and provides a TT Wing (battle royales only). Provides owner with 2 Flak Towers, Fortress & 2 Rocket/Gun/Tesla Towers in any battle where an opponent has forced it to be staked by selecting it themselves (ie you can't stake this territory, when you own it, to get the bonus forts as attacker, Chris!).