Precompressed air and electric power
In most cases at large airports the aircraft doesn't use its internal APU (a small turbine supplying both compressed air and electric power) to save noise, pollutants and cost.
Instead there are connections to the bridge, to a truck or to the ground. For example the preconditioned air circulates in these yellow pipes:
Other connections: Water, wasted water, fuel
There can also be other connections still in place (fuel, water, wasted water). The crew would need to disconnect corresponding pipes and cables, it's possible.
Everything must/can be disconnected
Here is a typical ramp scene for the A320, vehicles come and leave at different times:
Source: Airbus, Airport and Maintenance Planning.
The PIC (pilot in command of the aircraft) has extended powers when the aircraft doors are closed and start taxiing, this is not the case when the aircraft is not in operation. If the ground support crews don't want to execute pilot orders without their management approval, the aircraft crew can still go down the ramp using the bridge stairs (below the bridge on the first photo) to disconnect everything.
However they must no deteriorate the sockets, and it would be dangerous to just move the plane until the connections break, e.g. the refueling nozzle would likely stay in place, allowing fuel to leak from the tank (see mechanism here), with engines running a fire is almost certain.
Ramp obstacles
They may also have to move some truck or generator that would stay in way, but that should be manageable in case of extreme urgency.
Open doors, servicing panels, locking devices
There are other points to be considered, like open doors and panels (on engines, on cargo bays, etc), chocks in place, wheels moored with mechanical anchors. All of them are manageable. You can read about these elements on the same linked Airbus document, e.g. all the connection points are described at page 204, mooring anchors at page 190.
Risks associated with powerback
An author including such departure in a novel would be credible, providing the crew takes the related actions. Note using reverse thrust to taxi is possible but not entirely safe.
In normal conditions it would have to be validated by the operator and the airport using OpSpec C065.