Personally, I wouldn't do that. Before attempting any electrical modifications to shore power, make sure that you have a good understanding of how electricity works - in an RV it is not exactly like it is in a house. If you miswire, your insurance may not cover you in the event of a claim.
The 12-volt system uses the battery as a method of removing any rippling in the voltage - since shore power is 120-volts alternating current at 60 Hertz and the 12-volt system is direct current. The convertor converts the 120 vac to 12 vdc, but the battery smooths it out, especially in the older units. The 12 vdc runs the water pump, lights, furnace, and the controls to the refrigerator (the absorption is via heat from either 120 vac or propane).
As well, what if your generator won't start (it happens, you know).
1987 Excella 32-foot
1999 Dodge Ram 2500HD Diesel