The key to Long War is to NOT do the research Hyperspace Gates. That one will turn every gate-area mission into Destroy Object one. After that success the areas would turn into normal areas.
So, by not research it, we can have an invasion mission every few days for each owned gate area. A familiar mission with familiar enemies, familiar terrain, is a good farming mission.
I am planning to see if I can see the game fail due to running out of time.
OTOH, it could be troublesome when we want to research Written language of Martians. It require 3 artifacts, and we most likely have only two. More artifacts gather from excavation sites which are not always gate sites. So this require both checking Overview tabs, then check global world map. And double clicking on site name on Overview does not jump us to that area (a long time bug I think).