When it comes to air conditioning and generators out here, you need to think like an RVer boondocker (not parked next to a power source), because it's the same thing. The higher wattage but cheaper generators (3000 Watts, $350) are going to be the decibel level of your average lawn mower at about 90 decibels or more, and will get you kicked out of truck stops everywhere. Normal conversation is about 60 decibels. Most RV parks, urban areas and neighborhoods will restrict you to about 75 decibels for long term noise. An inverter generator will cost 2-3 times that of a loud generator, but they are in the 60 decibel range or less. The 1600 Watt rated
Honda i2000 is 59 at max load and the
Yamaha EF2000iS is 57 db. So is the
Wen 56200i. The Honda is by far the most popular out here because of reliability and ease of maintenance.
For rooftop air conditioners, go to a camping store like Camping World and see what they have. It's mostly Coleman and Dometic, but there are others. Do not think you can get a rooftop air conditioner with a heat strip and solve any heating issues. For heat you'll still want an Espar, or a propane heater (Espar is better).
There are plenty of people here who will answer your questions, let you know what will and will not work, what accessories you'll need, etc.. So before you go buy something, check in here.