ShapeShifter

Was this an IOTA transfer switch by any chance? Many were recalled by Monaco due to exactly the situation you are describing. The wires and contact blocks in the switch are much smaller than some other brands, and are prone to overheating. When you replace the switch, go with a more substantial brand. IF you just open up the cover and look inside, the difference in the size of the components is very obvious. Small wires and contact blocks mean more heat and more problems. while larger wires and contact blocks can better handle the current without overheating.

Seamless? No. While an automatic transfer switch is designed to automatically switch over between shore and generator power, it is not designed to do it while under a heavy load, like air conditioning. If under load when switching, the contacts can arc, resulting in burned contacts that don't make a connection, or welded contacts that won't break a connection. The auto transfer switch does make life easier. But the process is going to be pretty much what you describe: you will still want to turn off the A/C and other heavy loads before starting or stopping the generator and plugging or unplugging shore power. If you don't have a transfer switch now, I'm guessing you have an outlet that is powered by the generator, and you plug your shore cord into that? Getting an automatic transfer switch will save you the effort of having to do that part. I just bought this one: AirDream SofaBed Mattress It replaces a virtually identical and rather comfortable mattress that came with the sofa bed, and finally after seven years was replaced because the air portion started leaking significantly (resisting my patch attempts) and the springs were starting to sag. Hopefully this one will perform as well as the old one (haven't slept on it yet.)