smoking converter

Your situation concerns me a bit. The Converter has the job of taking 110 volts (either from your generator or from a campground electrical pedestal) and using it to keep your batteries charged. If the converter went smoking, it could signal something seriously wrong with your batteries (converter tried to supply too much current to a failing battery and ended up smoking itself). So the first thing I would do is disconnect my batteries and then measure their individual voltages. If you have 12v batteries, you should be measuring something in excess of 11.8 volts. If you measure less than 10v, you may have a bad battery. If you see any cracking of the battery case, any acid leaking onto the battery compartment, or a strong sulphur spell, then you do have a battery issue. But, if your batteries look good visually, then I'd put a battery charger on to the disconnected battery and let it sit for 4 hours. See if the battery takes a charge. If it does, reconnect it. If not, replace it.

The fact that you do not have 12v for your lights also points a shaky finger in the direction of your batteries. So that is somewhat consistent. Your A/C "might" have a thermostat that requires 12v to operate so that could be why it is not working. If your thermostat does not require 12v (and if the A/C doesn't need 12v for anything else), then the fact it does not turn on would also point to an A/C issue. I assume your microwave and TV work fine when plugged into shore power. If so, your A/C would be getting power unless you flipped the A/C circuit breaker when your converter fried.

There are lots of opinions here about converters. A good 3 stage converter is usually recommended by folks on this forum. Your challenge, unless you are handy doing your own maintenance, will be to select the appropriate converter and get it installed. Perhaps others will offer opinions on doing that as I've never replaced a converter.

Happy trails once you get this issue fixed!