Greetings Richard,
Technology has marched on since your coach was built. The charging profiles, self awareness of the equipment and user friendly application are all the result of years of needless failures. Almost everything out there electronically requires a "pure sine wave" to keep perfect time and operate as engineered.
If your going to replace your 20 year old inverter/charger, I would recommend the Magnum MS-2012 2000 watt with 100 amp 4 stage charger. You will also need a ME-RC 50 remote control. Aforementioned is a Pure sine wave inverter. Your microwave will thank you and current tablets, computers and future residential refrigerator.
Incidentally, trying to run your 100 amp coach on a 30 amp adapter is a challenge at best and a microwave would push you over your capacity if your water heater is on electric. Blessings & Joy, Fred