My Honda EV4010 is louder than my old flathead Onan 6K powerDrawer. The Honda runs higher RPM's.The Honda does have air cooled exhaust cowling, this helps with heat a lot. These are both RV built-ins.
However, I'm sure this thread is more about Honda Portable generators, and I will chime in about those too. My camping buddy has two EU2000i's. They are quiet, until the AC kicks on, or the Microwave kicks on, then they are as loud as anything else...
When it was 103* out in the desert, He had to turn eco-throttle off. A while later, one of them would stall occasionally at AC startup. It was random as to which one. They are both brand new. One is a Companion, so has the 30A plug.
At that point I knew that spending $900 on a used EV4010 with 80 hours on it was the better choice... At least for me, camping in the desert.
As for Forest Camping. The genset rarely gets used and never at night. People keep the darn things running so the kids can stay inside and watch tv. Drives me nuts. I run two 6V batteries and have 400W of solar on the roof. All I need.
I get that sometimes a furnace may run the batteries down. If that is the case, charge them with the genny during the day.