There is no atmosphere on Luna. A skid can accelerate on a linear rail line. It is in orbit when it reaches orbital velocity. A station in parallel low lunar orbit could hang a cable above a rail line. The cable could pick up the skid or just pick up cargo. The skid could also make contact and accelerate the station. The mass driver/track could be a small fraction of the length of an orbital ring. We have real demonstrations maglev rail systems.
The rail line would also function as a power line, pipeline, heavy cargo, and mass transit. It is just aluminum pipe. There is high concentrations of Thorium, Iron, and Titanium between 10 and 30 degrees west near the equator. Development will happen along the rail line. Assuming the mass driver is located near and parallel the equator a second line or road would lead to the polar water mines. A lunar space elevator will eventually be located at 0 degrees west.
The thorium map shows where uranium is likely to be found. Luna is an ideal location for nuclear reactors. There is no air or water to leak waste into. That allows for breeder reactors that would be considered risky on Earth. The reactors would be Luna's power supply at night. Radio isotope generators and nuclear engines will head outward.
The asteroid colonies will want the nuclear power supply.
Space stations using momentum exchange tethers need mass for momentum. The moon has absurd amounts of momentum. A series of stations in cis-lunar space can drop a rock into Earth's atmosphere/ocean. The stations can, of course, also de-orbit products or returning spaceships. Lunar rock could be used as radiation shielding for inhabited stations. The energy contained in any lunar material is higher than hydrocarbon supplies on Earth's surface.
Oxygen can be used as propellant. Momentum exchange tethers could gain acceleration from oxygen without even using any reactive fuel. One boost from the tank and a second if they jettison the gas. They would obviously heat the gas for added propulsion. Missions to the belt or beyond that use chemical rockets will be much cheaper if the ship does not need to haul oxygen off of Earth's surface. So even if the ships cannot use the tug from a tether the infrastructure would cut most of the mission launch cost.
Iron is available on the moon in metallic form and can be separated with a magnet. Iron oxide (rust) is very easy to separate into iron and oxygen. An aluminum smelter is more complex but could provide both oxygen gas and aluminum. Setting up the aluminum industry should be enough to get the infrastructure construction moving.