Of course they can. They can reach (some) orbit and go back to the ground again. For a low powered grav vehicle such as an air/raft it takes hours in either direction.
"Orbit" means both altitude and speed enough to stay there. An air/raft will not just float straight up to orbit, it has to accelerate sideways to get up to enough speed for the orbit. It will move away from the planet, accelerating sideways, moving out in a spiral until it reaches orbit.
If you watch a rocket launch you can see that the rocket isn't just going straight up. Its trajectory curves to the side so it can accelerate sideways up to orbital speed.
A grav vehicle is basically the equivalent of a small craft close to a planet, within about one diameter, except that they might not be vaccum-proof. A high powered grav vehicle can move to and from orbit just as quickly and easily as any spacecraft.
Air/rafts, grav floats, and grav belts are just limited by their low power. They have barely enough power to stay in the air, leaving very little power for propulsion.
So, a high powered (fast) grav APC should have no problems launching from a spacecraft in orbit, ferry troops to the ground, and go back again.