currently i got a problem that my base has a very largy solar/wind array, so my engineers had to walk a long way to maintanence them. However, there are a lot of disasters on my planet, and if i didn't get the forcast of them, those engineers far from base are likely get killed or badly injured. So i'm thinking that maybe we can allow a building lets call it "hideout". It can be built anywhere on the map and doesn't need to be connected, based on the size it can hold 2/4/6 people. your people will store food, water and even some backup power in it (basically anything your people need to survive for 1 day). So when they caught outside the base and you raise the alarm, they will seek for nearest hideout instead of walk a mile to the base and eventually die on their way(if it's nearer than the closet airlock and the airlock is further than some distance).

Beside that i'm thinking some "advanced airlock". Like a larger airlock which can allow more people go though it simultaneously. It was too slow even i have built 3 at same time pointing to the landing pad. Or build a X-ray airlock can detect weapons on intruders so your guards can go for them before they had a chance to shoot anyone.

Also for the trading, i think it's good to let the player store some items on the landing pad (so it works like a storage but only store what player ask them to do so) Otherwise when you making some big trade it takes days to deliver those foods/herbs/minerals to the trading ships. it allows player store say 50/100(for the airport) items in it and when trading those items will be used if chosen. (e.g. If i already have 20 vegetables in the landing pad, then i sell 30 vegetables, then my people just need to carry 10 more to the landing pad, save a lot of time)