getting the generator to work is only a stop gap measure.
it sounds like the batteries are low or dead. this would explain why no 12 volt power.
but you say you had it hooked up to the house. not getting 120 power could explain why the batteries went dead. they were connected to a load and not getting recharged.
so to me the real issue is to find out why you aren't getting 120 volt power when you were hooked up to the house. the best way to do this is to get the multimeter out and simply check for 120 volt power at each and every connection from the house receptacle to the rv distribution panel. do not assume, check it with a meter! once you can get 120 volt power to the rv the other problems will go away.
2015 cardinal model 3825fl
2015 dodge ram 3500 dually