If my RV's goes out, I'll just stick to 1G probably since I won't have time to mess about getting wires and a cheap 3G. I can get a 100A 1G for $121 from O'Reilly same or next day with a lifetime warranty. I don't even have the "house" batteries connected up the alternator since I went to lifepo4 batteries back in October, so 100A is plenty for what gets run, especially on an IDI where there's no electronic ignition system. I have 3 generators now (I recently trash picked an 2017 model, $600 2200/2500W inverter generator, and repaired it for ~$50 in parts) so I have ways to get around a bad alternator a couple days if need be.