I don’t think I can give you an answer about trips beyond Earth orbit, but from what I've read in the near term any railgun would only be able to send small payloads into space.
The biggest obstacles would be the needed power to run your maglev as well as the heat that these satellites would have to endure at launch. Also, launch forces due to acceleration might be quite high, requiring specially reinforced electronic packages.
The Navy has experimented with a railgun and I believe that system can develop speeds up to 6 km/sec for small projectiles. That’s close to the required orbital velocity of 8 to 10 km/s. Yet even a satellite with an optimal aerodynamic fairing (picture a highly streamlined Explorer 1 from the 1960s for relative size and shape) would experience velocity losses due to friction, drag, and gravity. That loss can add up to almost 3 km/s. So, the total velocity to get into LEO required b y your satellite is between 11 to 13 km/s, I believe.
Your maglev launch system would likely look a lot like the launcher in “When Worlds Collide,” where it goes up the side of a mountain. Only instead of riding on a track the satellite would blast through a ringed tunnel. Those rings are electromagnets and they alternately grab and propel your sat toward the exit on the launcher. These have to be powered b y capacitors that can hold something on the order of 36 M-Joule. That’s huge! The power required would be on the order of 2 G-Watts. The acceleration on this system is about 10000 times the force of gravity, however despite losses a small 1-kg payload could reach over 100 km about 2 minutes. It's speed would be roughly Mach 6, which is maybe a quarter of the Mach 25 something in orbit flies at. That Mach 6 sounds good, but this would be a sub-orbital flight. The package would follow a ballistic arch and after some time would drop back to earth. Sort of like a sounding rocket.
To go higher and achieve orbit in the near term, your maglev concept might be used to launch a sat but the sat would carry a rocket motor which could give it enough thrust to achieve orbit. This could be used for cube-sats and small payloads under maybe 5-kg. I know that sounds disappointing to use a rocket with your maglev system
however the current state of the art might require it until something more powerful is developed. Pewrhaps if the railgun was carried via balloon or plane that might work, although again, the power requirements are pretty stringent. The Navy tests were promising, but I think they only made a few test shots. To have an effective launcher you will need to be able to do this repeatedly with little down time in between.
Hope that answers your question.
RSR