I think that you already figured out that if you use the microwave and toaster oven at the same time that it will trip the circuit breaker. Same with toaster and coffee maker, or coffee maker and microwave.
If you figure out what is 'not' on the microwave circuit, then you can plug in the toaster oven to the non-microwave receptacle, and then run both at the same time.
Or have a electrician install a new receptacle powered directly from your 50 amp electrical panel that is not on the inverter circuits.
The inverter normally is powered by a 1 pole 30 amp breaker. It will use power to run both inverter output circuits as well as charge the battery.
Battery charging normally will only take 2-4 amps. More is used to run the 15 or 20 amp outputs that 'pass through' the inverter wiring to the receptacles on the RV. Tripping the 30 amp inverter circuit breaker should be rare!
Have fun camping!
Fred.