You are going to have to step by step trace the power from the batteries to the fuse panel. The chassis battery is suspect since you were working on the dash radio/camera. Check at the battery disconnect solenoid for power. On many disconnect solenoids, there are actually fuses on the solenoid body, check that they are good. If you jumper the two large terminals on the solenoid, you'll bypass it completely. If still no power, you should go back to the battery and trace the large wires to the disconnect. There should be a large circuit breaker, make sure it's not tripped.
You'll have to repeat the same steps on the house batteries. They are the ones that power the overhead lights, water pump, thermostat (that controls the A/C) and many other systems.