I'm not really understanding why it's hard to get propane either. You do have to know the types of places that sell propane including truck stops and rv parks, for instance. My tanks last a really long time, but I don't run my generator for long periods of time.
I can't say why some people have issues with the Onan, but I don't. All I can tell you that other than replacing the oil with a very good synthetic, I've done nothing to mine and I've had my TC 9 1/2 years. I don't think I even have 100 hrs on it. I use my Onan for two primary things, 1. Top off the batteries, 2. Run the major electric appliances like Microwave and Keurig single cup coffee maker when I'm not using the inverter.
As far as using the AC on a smaller generator goes .... here are some ideas
1. do make sure you set the fridge to propane only
2. unplug your battery charger.
3. if you have an option on your AC use the low setting at least at start.
I was thinking about getting a small gasoline generator to charge my batteries, but it seems for most of my camping it's not needed since I added LED lights.
