Roof mounted = AC, Antennas, camera, solar, vent fans and similar.
Under roof mounted = lights, speakers and overhead furniture.
Wire routing required = battery bank, inverter, converter, disconnect switching, brake breakaway system, tongue jack, entertainment electronics, communications electronics, lighting, fans, AC power and control, solar system,
12 volt and 120 volt. Control, power and repair considerations are required for the systems.
Then there are alarm and similar security systems.
Note there are also code, best practices, premium approaches, and specific application design standards that can be considered or ignored.
Helps a lot to have the systems designed prior to the raceway designs. Standard practice should include wire pull cords and enough space to add future cable requirements.
You need to freeze the design at some point in time so you can move forward with your project. Budgets are often the driver that helps with clamping design creep. Note - the final design needs to only support your RV lifestyle. It's your coach, your budget and your decision.
Good luck - likely missed some items - hope some you had not considered are included above. Have fun. Pat