The first reply on this thread and the chart Dakota98 posted are really, really good.
As has been noted, you can get the AC running in most situations with a 3100. But the trade off is in weight and you don't need all of the capacity when you aren't needing AC. So most often people will go with a paired set of 2000 units. That way you can run (or even only take) just 1 if all you need are your batteries charged and the ability to run the microwave, etc.
I spent last weekend dry camping at a CG where we believe a full half of the RVs there were using generators. First time we've seen that many as a percentage. Number one in quantity were the Hondas, and pleasantly surprised to see some going as small as a 700. We walked by Class A and Class C motorhomes with onboard units that sounded louder than the Hondas. And we saw one guy with a toyhauler who had consistent problems getting his onboard started (at 8,600 ft elevation).
And then there was the 1 open-frame generator. It's not just that it was louder, the mechanical noise (not just the exhaust) is part of what makes it cringe-worthy. Luckily they only ran it a little.
I mentioned the altitude earlier and that's part of why I have a single Honda EU2000i. I have the high-altitude jet for the carburetor and can change it out in under 30 minutes (at home). All my camping for the next couple of months will be at 7,000-10,000 ft, so I already made the swap. And if I need the AC, I can buy a second EU2000i and pair them.
