Well you are in luck!
The QD7500 service schedule calls for oil and oil filter change every 150 hours
Air filter service is longer, but it is inexpensive and you access both the oil drain plug, oil filter and air filter from underneath the generator---no need to drop the unit. You may as well change both while you are down there.
As far as the spark arrestor goes, there are videos on the net that will demonstrate the method required to clean it. You will not need to drop the generator to perform this maintenance.
Fuel filter change is also a recommended PM. Also accessible from below and no need to drop the generator.
Dave
1998 American Eagle 40EVS