Using RV generator as a backup generator for the house?

Before doing much more thinking of the RVs genset, determine what you want to run. Make a list of wattage of items.
240 volt pump could be a very major concern. amperage of it's starting could go over many portable gensets as well.
Sure you could get a transformer and back feed it to get 240 volts from 120 but it will cost to wire it up properly.