While at my Ranch in Idaho I split the 50 amp cord with two 30 amp cords with the adapter made by Liberty (1-50amp240 volt female recepticle in a 4-s box and two 30 amp 120 volt pigtail and cord caps ) Then with two 50 fooot cords i pluged into two seperate circuits , 1-30 amp and 1-20 amp.
It worked ok but not great because the inverters charge and use some of the juice as well. Next year I am going to up grade the service and the RV sites.