Champion 75531i 3100w Inverter Generator

When it comes to high altitude I can tell you that it takes a fair chunk of power away from the generator. Even using a 3500/4000 I have to be sure our battery isn't charging off of the converter before I try starting our 13.5 AC unit. That is at 9200 ft, the generator doesn't even burp at 5280 ft where we live. So if you plan on being at altitude I would suggest getting as much headroom as you can.
In our case a hard start capacitor and having the battery already charged up by solar should make a big difference for us.