Base building.
So we could build our bases and cosmodromes where we want them to be built. It would cost us money, resources and would last 6 months to 10 years. We could also deliver resources to building sites. So we may build our airfields, bases and cosmodromes on multiple places, not like in KSP we have only one. While building on other cellestial bodies, we may also deliver special resources. The builds we could build would be: rocket hangar, upgradeable, $10mln and upgrades 1.5 times more than first one, $100k;
Rocket launch pad (or cosmodrome in further time) $2mln and each upgrade 1.5x$10k;
Plane hangar, $5mln, upgrades like for launchpad;
Airfield, $100k to $800k, may vary from it's lenght, no upgrades;
Mine, Smearth $3mln, asteroids $8mln, moons and planets $12mln, upgrades would cost 10% of main price;
Ground vehicle building centre, price on Smearth $4mln, on other cellestial bodies $11mln, upgrades as for mine;
Basic infrastructure (research centre, radar centre, hangars and homes for astronauts $10k to $5mln);
And whatever you can think of to add. Hope it will at least give you some ideas.